Happening @ Michigan https://events.umich.edu/list/rss RSS Feed for Happening @ Michigan Events at the University of Michigan. CM/AMO Seminar | Single-particle Theory of Optical Scattering from Atomic Clusters (December 11, 2018 4:00pm) https://events.umich.edu/event/58225 58225-14444065@events.umich.edu Event Begins: Tuesday, December 11, 2018 4:00pm
Location: West Hall
Organized By: Department of Physics

We have recently demonstrated that a dense ensemble of two-level atoms driven by an electromagnetic field can be modelled by an effective single quantum system that has a time-varying decoherence rate [1]. This model compares very well to large-scale, mean-field simulations of the Maxwell-Lindblad equations for a cluster of approximately 4000 atoms. Our effective single particle theory provides a way to model optical interactions in clusters in which computational time can be reduced, and also a model in which the underlying physical processes involved in the system's evolution are much easier to understand. We use this theory to provide an explanation for the results of scattering experiments [2], in which high-intensity, short-duration, electromagnetic pulses were scattered off dielectric liquids such as water and carbon tetrachloride, and produced depolarized emission patterns.

[1] C. S. DiLoreto and C. Rangan, Phys. Rev. A 97: 013812, 2018.
[2] S. C. Rand, W.M. Fisher, and S. L. Oliveira, J. Opt. Soc. Am B, 25:1106, 2008.

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Workshop / Seminar Tue, 11 Dec 2018 18:15:46 -0500 2018-12-11T16:00:00-05:00 2018-12-11T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | What is space weather, and why should you care? (January 9, 2019 4:00pm) https://events.umich.edu/event/58910 58910-14578297@events.umich.edu Event Begins: Wednesday, January 9, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The continuous outflow of plasma from the Sun fills the heliosphere with tenuous gas of charged particles carrying the Solar magnetic field. Largely shielded by the internal geomagnetic field, only a small fraction of the protons and electrons make it to the near-Earth space - but those that do, have a strong impact on our electromagnetic and radiation environment. As the society increasingly relies on space-based assets, it has increasingly important to develop preditions of high-energy (keV to MeV) particle fluxes in the near-Earth space. This talk discusses the effects of Coronal Mass Ejections from the Sun as they reach the geospace: The bright auroral displays, ground currents harmful to power networks and other infrastructure, and the radiation belt electrons in regions where the navigation and communication satellites reside. Our methodologies include satellite observations of the Sun and the fields and plasmas in near-Earth space, and large-scale numerical models to model the complex interactions between the solar wind and the geospace plasma environments.

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Workshop / Seminar Wed, 09 Jan 2019 18:16:01 -0500 2019-01-09T16:00:00-05:00 2019-01-09T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
CM Theory Seminar | Dirac Electrons on the Kagome Lattice (January 10, 2019 4:00pm) https://events.umich.edu/event/58911 58911-14578298@events.umich.edu Event Begins: Thursday, January 10, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The kagome lattice is a two-dimensional network of corner-sharing triangles known as a platform for exotic quantum magnetic states. Theoretical work has predicted that the kagome lattice may also host exotic Dirac electronic states including those with non-trivial topology. We here present our recent work in conducting, layered kagome materials in exploring these Dirac-like states, particularly in systems with magnetic order. We describe observations massive Dirac states and associated Berry curvature induced transport. We also demonstrate the detection of these states from de Haas-van Alphen oscillations and their modification in magnetic field. Finally, we discuss the promise for these materials in terms of realizing robust time-reversal-breaking topological phases.

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Workshop / Seminar Thu, 10 Jan 2019 18:16:00 -0500 2019-01-10T16:00:00-05:00 2019-01-10T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Life After Graduate School Seminar | Building Skynet: How an ultrafast optics physicist became a robotic AI researcher (January 11, 2019 12:00pm) https://events.umich.edu/event/59120 59120-14686286@events.umich.edu Event Begins: Friday, January 11, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Tim Saucer will present a brief introduction of his path from physics graduate school to working in private industry, followed by a longer discussion of how to navigate the job search process.

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Workshop / Seminar Fri, 11 Jan 2019 18:16:07 -0500 2019-01-11T12:00:00-05:00 2019-01-11T13:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
How to Make Causal Inferences Using Texts (January 11, 2019 4:00pm) https://events.umich.edu/event/59075 59075-14677952@events.umich.edu Event Begins: Friday, January 11, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: New text-as-data techniques offer a great promise: the ability to discover, measure, and then utilize text-based variables for testing social science theories of interest from large collections of text. We introduce a conceptual framework for making causal inferences with text-based measures as either a treatment or outcome.  We argue that nearly all text-based causal inferences depend upon a latent representation of the text and provide a set of sufficient assumptions to identify causal effects when text is used as a treatment or outcome. We provide a framework to learn the latent representation---justifying the use of popular unsupervised methods such as topic modeling or principal component analysis---and then estimate causal effects with the same sample used to learn the latent representation. But estimating the latent representation, we show, creates new risks: we may introduce an identification problem or overfit. To address this problem we introduce a split-sample framework.  We apply our framework to study whether increasing the proportion of women on Congressional committees leads to more representation of women’s ideas during the legislative process and to assess how partisans respond to social media messages from President Trump.

Bio: Justin Grimmer is an associate professor of political science at Stanford University. His research examines how representation occurs in American politics using new statistical methods. His first book Representational Style in Congress: What Legislators Say and Why It Matters (Cambridge University Press, 2013) shows how senators define the type of representation they provide constituents and how this affects constituents' evaluations. His second book The Impression of Influence: How Legislator Communication and Government Spending Cultivate a Personal Vote (Under Review, with Sean J. Westwood and Solomon Messing) demonstrates how legislators ensure they receive credit for government actions. His work has appeared in the American Political Science Review, American Journal of Political Science, Journal of Politics, Political Analysis, Proceedings of the National Academy of Sciences, Regulation and Governance, and Poetics. During the 2013-2014 academic year he was a National Fellow at the Hoover Institute.

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Workshop / Seminar Wed, 02 Jan 2019 13:12:20 -0500 2019-01-11T16:00:00-05:00 2019-01-11T17:00:00-05:00 West Hall Michigan Institute for Data Science Workshop / Seminar Justin Grimmer, PhD
Quantitative Biology Seminar (January 14, 2019 12:00pm) https://events.umich.edu/event/59059 59059-14677934@events.umich.edu Event Begins: Monday, January 14, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Quantitative Biology Seminar

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Workshop / Seminar Mon, 14 Jan 2019 18:16:09 -0500 2019-01-14T12:00:00-05:00 2019-01-14T13:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | The Global Electroweak Fit in the Light of the New Results from the LHC (January 14, 2019 4:00pm) https://events.umich.edu/event/58683 58683-14544786@events.umich.edu Event Begins: Monday, January 14, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

With the high integrated luminosities recorded at the LHC and the very good understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. In this talk, I review the measurement of the W boson mass as well as the measurement of the electroweak mixing angle with the ATLAS detector, both achieving highest precision after several years of intense effort. Special focus is drawn on a discussion of the modeling uncertainties as well as the physics potential of the latest low-mu runs, recorded at in 2017 and 2018. The results will be interpreted in terms of the overall consistency of the Standard Modell by the global electroweak fit, performed by the Gfitter Collaboration.

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Workshop / Seminar Mon, 14 Jan 2019 18:16:09 -0500 2019-01-14T16:00:00-05:00 2019-01-14T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Towards an Inclusive Physics (January 16, 2019 4:00pm) https://events.umich.edu/event/59060 59060-14677935@events.umich.edu Event Begins: Wednesday, January 16, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Three kinds of data are relevant to diversity, equity, and inclusion in physics and other fields. Quantitative data about demographics (e.g., race and binary gender, and less often sexual orientation, other social identities, and their intersections) are widely available; student degree completion data from Michigan, MIT and other departments will be compared. Quantitative and qualitative data about the learning and work environment are sometime available, as in the 2016 Michigan Campus Climate Survey and in experiences shared by individuals. An institution’s policies and practices represent a third kind of data useful in guiding a department. This presentation will share three case studies on data-driven change from different departments at MIT and will reference recent recommendations from professional societies (APS, AAS, AAAS, NASEM) for improving equity and inclusion.

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Workshop / Seminar Wed, 16 Jan 2019 18:16:14 -0500 2019-01-16T16:00:00-05:00 2019-01-16T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Astronomy Colloquium Series Presents (January 17, 2019 3:30pm) https://events.umich.edu/event/58457 58457-14502339@events.umich.edu Event Begins: Thursday, January 17, 2019 3:30pm
Location: West Hall
Organized By: Department of Astronomy

Physics and phenomenology of galactic winds

Abstract: Galactic winds are a crucial ingredient in galaxy evolution, but the physics of the ubiquitous outflowing high velocity gas seen from rapidly star-forming galaxies remains unknown. I will describe a series of projects designed to shed light on these open questions, with a focus on how to produce cool atomic and warm photo-ionized gas at high velocities. One idea is to precipitate the cool gas from the super-heated hot phase on scales outside the host galaxy. Another option is to directly accelerate the cool gas from the galaxy with momentum injection, perhaps provided by radiation pressure on dust, cosmic rays, or a putative fast, hot wind. I'll highlight challenges on both the observational and theoretical fronts, and connect to observational constraints on physical scales ranging from the host galaxy's molecular clouds to its circumgalactic medium.

Should you require any reasonable accommodations to ensure equal access and opportunity related to this event, please contact Stacy Tiburzi at 734-764-3440 or stibu@umich.edu.

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Lecture / Discussion Wed, 09 Jan 2019 11:54:07 -0500 2019-01-17T15:30:00-05:00 2019-01-17T16:20:00-05:00 West Hall Department of Astronomy Lecture / Discussion Dr. Todd Thompson
A nAttractor Mechanism for nAdS(2)/nCFT(1) (January 18, 2019 3:00pm) https://events.umich.edu/event/59610 59610-14754562@events.umich.edu Event Begins: Friday, January 18, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

High Energy Theory Talk

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Lecture / Discussion Fri, 18 Jan 2019 13:16:43 -0500 2019-01-18T15:00:00-05:00 2019-01-18T16:00:00-05:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
HET Seminars | An Attractor Mechanism for nAdS(2)/nCFT(1) (January 18, 2019 3:00pm) https://events.umich.edu/event/59653 59653-14777840@events.umich.edu Event Begins: Friday, January 18, 2019 3:00pm
Location: West Hall
Organized By: HET Seminars

TBD

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Workshop / Seminar Mon, 14 Jan 2019 08:32:18 -0500 2019-01-18T15:00:00-05:00 2019-01-18T16:00:00-05:00 West Hall HET Seminars Workshop / Seminar West Hall
The Michigan Anthropology Colloquia Series: "Mississippian Migration and Polity Formation in Central Alabama: Conflict or Communitas?" (January 18, 2019 3:00pm) https://events.umich.edu/event/51871 51871-12274331@events.umich.edu Event Begins: Friday, January 18, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"Mississippian cultural practices appear somewhat later in Central Alabama than in other regions of the Southeastern United States. Although evidence of trade and exchange between Late Woodland communities in the region and Mississippian groups is present, it appears as though local Woodland groups were reluctant to fully embrace what archaeologists have defined as “classic" Mississippian culture. This talk centers on archaeological research at several Terminal Woodland sites in Central Alabama, highlighting cases where interactions with Mississippian groups generated archaeological remains that can be interpreted as either evidence of conflict or communitas as initial Mississippian settlement of the region took place."

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Fri, 11 Jan 2019 12:43:58 -0500 2019-01-18T15:00:00-05:00 2019-01-18T17:00:00-05:00 West Hall Department of Anthropology Lecture / Discussion West Hall
Information Extraction from Online Text --- from Opinions to Arguments to Persuasion (January 18, 2019 4:00pm) https://events.umich.edu/event/59488 59488-14745558@events.umich.edu Event Begins: Friday, January 18, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: A long line of research in Natural Language Processing (NLP), including our own, has addressed the task of identifying and extracting information about opinions with the goal of determining what people (and other entities) are thinking or feeling. In this talk, I'll present new research on argument mining, a relatively new area of study in NLP that focuses less on extracting from text WHAT people think or feel, but rather analyzing argumentative text to understand WHY they do so. Specifically, I will first present some of our new research on the automatic analysis of informal, user-generated arguments in which we aim to expose the intended underlying structure of the argument. Next, I'll present our research that examines arguments on a public debate forum to understand what makes one argument more convincing than another.

Bio: Claire Cardie is the John C. Ford Professor of Engineering in the Departments of Computer Science and Information Science at Cornell University. She was the founding Chair of Cornell's Information
Science Department and has worked in the area of topics ranging from information extraction, text summarization and noun phrase coreference resolution to the automatic analysis of opinions, sentiment and deception in text. Cardie was selected as a Fellow of the Association for Computational Linguistics in 2015. She has served on the executive committees of the ACL, NAACL and AAAI, and has been Program Chair for EMNLP, CoNLL, ACL and COLING as well as General Chair this past July for ACL 2018 in Melbourne.

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Workshop / Seminar Thu, 10 Jan 2019 13:57:49 -0500 2019-01-18T16:00:00-05:00 2019-01-18T17:00:00-05:00 West Hall Michigan Institute for Data Science Workshop / Seminar Claire Cardie, PhD
Astronomy Colloquium Series Presents (January 24, 2019 3:30pm) https://events.umich.edu/event/58458 58458-14502340@events.umich.edu Event Begins: Thursday, January 24, 2019 3:30pm
Location: West Hall
Organized By: Department of Astronomy

“Origin of Molecular Clouds in Early Type Galaxies”

The Atacama Large Millimeter Array has changed our view of molecular clouds in central cluster galaxies. Unlike spiral galaxies where molecular gas lies in a disk moving in ordered motion about the center of the galaxy, molecular clouds in cluster centrals likely form in the updrafts of rising radio bubbles. Less is known about molecular gas in normal giant ellipticals. However, trends between the thermodynamic properties of the hot atmospheres in normal elliptcals and cluster centrals suggests much of the molecular gas in ellipticals condensed from their hot atmospheres.

Should you require any reasonable accommodations to ensure equal access and opportunity related to this event, please contact Stacy Tiburzi at 734-764-3440 or stibu@umich.edu.

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Lecture / Discussion Tue, 15 Jan 2019 12:48:55 -0500 2019-01-24T15:30:00-05:00 2019-01-24T16:20:00-05:00 West Hall Department of Astronomy Lecture / Discussion Dr. Brian McNamara
Dark Matter Production: Finite Temperature Effects in the Early Universe (January 25, 2019 3:00pm) https://events.umich.edu/event/60030 60030-14814795@events.umich.edu Event Begins: Friday, January 25, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

In the early universe, the Standard Model particles formed a hot thermal bath. We highlight the importance of finite temperature corrections in these conditions on various production mechanisms of dark matter, primarily through temperature dependent masses and scalar vevs. We first consider a variation on standard freeze-out, where kinematic thresholds determine the relic abundance. We then consider a freeze-in model where the production rate is dramatically increased when a kinematic threshold opens. Finally, we present a qualitatively new production mechanism for dark matter, where dark matter decay is allowed for a limited amount of time just before the electroweak phase transition.

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Lecture / Discussion Mon, 04 Feb 2019 13:15:24 -0500 2019-01-25T15:00:00-05:00 2019-01-25T16:00:00-05:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
The Michigan Anthropology Colloquia Series: "Rally Days: Violence and Political Aesthetics in post-war Sierra Leone" (January 25, 2019 3:00pm) https://events.umich.edu/event/52365 52365-12650113@events.umich.edu Event Begins: Friday, January 25, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"In March, 2018, voters in Sierra Leone went to the polls to elect a new president. These were arguably the first post-war elections in this West African state in which the dominant parties did not threaten to remobilize veterans of the country's long recent war. But this did not mean the end of violence in Sierra Leonean political campaigns. Violence and the threat of violence remain an integral part of the political imaginary in national politics. Drawing on film footage from the final rally days of the various political parties, I explore in this talk the fundamental role of violence in Sierra Leone's political aesthetics."

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Tue, 04 Dec 2018 08:37:41 -0500 2019-01-25T15:00:00-05:00 2019-01-25T17:00:00-05:00 West Hall Department of Anthropology Lecture / Discussion West Hall
Quantify Systematics from Mislabeled Truth Tables in Supervised Learning (January 25, 2019 4:00pm) https://events.umich.edu/event/59978 59978-14806102@events.umich.edu Event Begins: Friday, January 25, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: Many real world classification problems use ground truth labels created by human annotators. However, observed data is never perfect, and even labels assigned by perfect annotators can be systematically biased due to poor quality of the data they are labeling. This bias is not created by the annotators from measurement error, but is intrinsic to the observational data. We present a method for de-biasing labels which simultaneously learns a classification model, estimates the intrinsic biases in the ground truth, and provides new de-biased labels. We test our algorithm on simulated and real data and show that it is superior to standard denoising algorithms, like instance weighted logistic regression. We apply our technique to galaxy images and find that the morphologies based on supervised machine-learning trained over features such as colors, shape, and concentration show significantly less bias than morphologies based on expert or citizen-science classifiers. This result holds even when there is underlying bias present in the training sets used in the supervised machine learning process.

Bio: Chris Miller is a leader in astroinformatics – mixing computer science, advanced statistics, and data mining to answer key cosmological questions. His specialty is using galaxy clusters to trace the distribution of matter in the universe. After years exploiting the Sloan Digital Sky Survey, he is now heavily involved in the Dark Energy Survey and Dark Energy Spectroscopic Survey, two of the largest current astronomical survey efforts. Professor Miller used his galaxy-cluster research to support the Big Bang theory by aligning findings from opposing cosmological epochs. He was the first to see the signatures of sound waves from the very early universe that were “frozen into” the matter-density distribution that we observe today. His analysis of the current universe synched neatly with the acoustic oscillations of the early universe detected in the cosmic microwave background, and demonstrated the power of combining big-survey with focused observational follow-up data. He has published in a variety of journals outside his own fields of physics and astronomy, including NIPS, ICPR, The Annals of Applied Statistics, and Statistical Science.

Background: BS, Penn State; PhD, University of Maine. Postdoc (2000-2005) Carnegie-Mellon; Faculty (2005-2009) National Optical Astronomy Observatory/Chile. Hired in 2010 at U-M under a presidential initiative for advancing data mining research.

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Workshop / Seminar Thu, 17 Jan 2019 17:29:47 -0500 2019-01-25T16:00:00-05:00 2019-01-25T17:00:00-05:00 West Hall Michigan Institute for Data Science Workshop / Seminar Chris Miller, PhD
HEP-Astro Seminar | Axions, Direction Detection, and ABRACADABRA (January 28, 2019 4:00pm) https://events.umich.edu/event/60274 60274-14857771@events.umich.edu Event Begins: Monday, January 28, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The axion is a promising dark matter candidate which was originally proposed to solve the strong CP problem in particle physics. To date, the available parameter space for axion and axion-like particle dark matter is relatively unexplored, particularly at axion masses less than 1 mu eV. ABRACADABRA is a new experimental program to search for axion dark matter over a broad range of masses, 10−12 < m_a <10−6 eV, and ABRACADABRA-10 cm is a small-scale prototype for a future detector that could be sensitive to the QCD axion. Recently, a one-month data collection with ABRACADABRA-10 cm lead to the first results in the search for axion dark matter by the ABRACADABRA collaboration. In this talk, I will: review the theoretical and experimental status of axion physics; describe the construction of the ABRACADABRA-10 cm detector, the data collection, and the analysis leading to new laboratory-based constraints on the axion; and discuss future prospects for the ABRACADABRA program.

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Workshop / Seminar Mon, 28 Jan 2019 18:16:47 -0500 2019-01-28T16:00:00-05:00 2019-01-28T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO / CM Theory Seminar | Accurate Modeling of Charging Energies in Systems with >10,000 Electrons with StochasticGW (January 29, 2019 4:00pm) https://events.umich.edu/event/60135 60135-14840442@events.umich.edu Event Begins: Tuesday, January 29, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Stochastic Quantum Chemistry (SQC) is a new paradigm we developed for electronic structure and dynamics, which rewrites traditional quantum chemistry as stochastic averages, avoiding the steep power law scaling of traditional methods. As an example I will discuss Stochastic GW (SGW). The GW technique is known to achieve high accuracy, with only a 0.1-0.3 eV experiment-theory deviation for affinities and ionization energies. SGW reproduces the results of traditional deterministic GW for small systems, but also handles very large systems; as an example, we easily calculated affinities, charging energies, and photoelectron spectroscopy for Si clusters and Si and P platelets with up to 11000 valence electrons, for clusters with 40 thiophene molecules, and for periodic systems with very large supercells. These systems are significantly bigger than any calculable in existing approaches, so that SGW makes a quantum jump in the ability to calculate accurate electronic affinities and potential energies for large molecules. We will specifically discuss recent improvements in the algorithm and implementation which makes SGW superior to traditional techniques already for tetracene, and reduces experiment-theory deviations to ~0.1eV.

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Workshop / Seminar Tue, 29 Jan 2019 18:16:52 -0500 2019-01-29T16:00:00-05:00 2019-01-29T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Astronomy Colloquium Series Presents (January 31, 2019 3:30pm) https://events.umich.edu/event/58568 58568-14511741@events.umich.edu Event Begins: Thursday, January 31, 2019 3:30pm
Location: West Hall
Organized By: Department of Astronomy

"Solar System History via Near-Earth Asteroids (...and NASA's OSIRIS-REx Space Mission)"

We report on the current status and scientific results of NASA's OSIRIS-REx sample return mission that is visiting the B-type near-Earth asteroid (101955) Bennu. The spacecraft launched in September 2016, arrived at Bennu in December 2018 and will survey and study the asteroid until attempting to collect a sample in the summer of 2020 and return it to Earth in 2023. What will be learned from studying and sampling one near-Earth Asteroid?

Near-Earth Asteroids (NEAs) are transients that have escaped the Main Asteroid Belt and spend a paltry 10 Myr on planet-crossing orbits before hitting the Sun, a planet or getting ejected from the Solar System. All of the various taxonomic types of asteroids are represented amongst NEAs, but due to their chaotic orbits it is not possible to precisely retrace their history and determine where in the Main Asteroid Belt they came from. Furthermore, km-sized NEAs, are unlikely to have survived Solar System history intact and are expected to be reaccumulated remnants from a larger disrupted asteroid - they are often referred to as "rubble piles". In sum, any given small NEA comes from an unknown place and has an unknown parent asteroid and history. However, with Bennu, ultimately, returned samples from Bennu should clarify its history and evolution, and in the meantime its geology can reveal much of its history and shed light on its history in the Main Asteroid Belt.

Should you require any reasonable accommodations to ensure equal access and opportunity related to this event, please contact Stacy Tiburzi at 734-764-3440 or stibu@umich.edu.

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Lecture / Discussion Wed, 16 Jan 2019 12:35:05 -0500 2019-01-31T15:30:00-05:00 2019-01-31T16:20:00-05:00 West Hall Department of Astronomy Lecture / Discussion Dr. Kevin Walsh
HET Seminars | From Seiberg-Witten Theory to Adjoint QCD (February 1, 2019 3:00pm) https://events.umich.edu/event/60482 60482-14899149@events.umich.edu Event Begins: Friday, February 1, 2019 3:00pm
Location: West Hall
Organized By: HET Seminars

TBD

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Workshop / Seminar Mon, 28 Jan 2019 09:07:52 -0500 2019-02-01T15:00:00-05:00 2019-02-01T16:00:00-05:00 West Hall HET Seminars Workshop / Seminar West Hall
The Michigan Anthropology Colloquia Series: "Quantitative analyses of the early ape Ekembo with implications for hominoid evolution" (February 4, 2019 3:00pm) https://events.umich.edu/event/51780 51780-12248759@events.umich.edu Event Begins: Monday, February 4, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Tue, 29 Jan 2019 10:07:17 -0500 2019-02-04T15:00:00-05:00 2019-02-04T17:00:00-05:00 West Hall Department of Anthropology Lecture / Discussion West Hall
HEP-Astro Seminar | Fermilab: The Accelerators that Drive the Science (February 4, 2019 4:00pm) https://events.umich.edu/event/60136 60136-14840443@events.umich.edu Event Begins: Monday, February 4, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

In May 2014 the Particle Physics Project Prioritization Panel (P5), which advises the US Department of Energy (DOE) Office of High Energy Physics released a report called "Building for Discovery" a Strategic Plan for U.S. Particle Physics in the Global Context. The top accelerator-based priorities for Fermilab are: to support the LHC and its planned luminosity upgrades, pursue the g-2 and Mu2e muon programs, focus on the high energy neutrino program to determine the mass hierarchy and measure CP violation, and engage in modest and appropriate levels of ILC accelerator R&D. In this context, I will look at the current accelerator complex, recent upgrades, current projects, accelerator R&D, and ideas/concepts for longer-term future.

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Workshop / Seminar Mon, 04 Feb 2019 18:16:57 -0500 2019-02-04T16:00:00-05:00 2019-02-04T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
CM/AMO Seminar | Visualizing a relativistic quantum Hall liquid in a graphene quantum dot (February 5, 2019 4:00pm) https://events.umich.edu/event/59989 59989-14808246@events.umich.edu Event Begins: Tuesday, February 5, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Creating and probing the spatial and/or magnetic confinement of particles is ubiquitous in physics, from thermonuclear fusion to ultracold atoms. Spatial confinement leads to the well known "particle-in-a-box"-like states that describe electron behavior in quantum corrals and semiconductor quantum dots (QD). Magnetic confinement leads to charged particles performing tight cyclotron motion and is responsible for the integer quantum Hall effect, a striking example of a macroscopic topological quantum state of matter. But what happens when we finely tune from spatial to magnetic confinement, and what role do electron interactions play?

In this talk I will present scanning tunneling microscopy/spectroscopy (STM/S) measurements that explore the interplay between the spatial and magnetic confinement of massless Dirac fermions in a custom 'rewritable' graphene quantum dot. I will first describe how graphene electrons can form quasi-bound QD states due to relativistic Klein scattering. As a magnetic field is applied, I will show measurements that directly visualize the intricate evolution of the atomic shell-like QD states into highly degenerate Landau levels. Here, increased electron interactions lead to the subsequent formation of a 'wedding cake' structure of compressible-incompressible electron strips, showing that custom-made QDs are a new platform for corralling quantum Hall liquids.

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Workshop / Seminar Tue, 05 Feb 2019 18:16:55 -0500 2019-02-05T16:00:00-05:00 2019-02-05T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Conformal Field Theory: From Boiling Water to Quantum Gravity (February 6, 2019 4:00pm) https://events.umich.edu/event/60650 60650-14937065@events.umich.edu Event Begins: Wednesday, February 6, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Conformal Field Theory (CFT) is a framework used to describe physical systems with no intrinsic length or energy scales. CFTs have wide applicability across theoretical physics, ranging from boiling water or magnets at criticality to the low-energy dynamics of extended objects in string theory. In this talk, I will begin by describing how CFTs can be used to understand critical phenomena, and then I will discuss a couple of recent ideas that led to tremendous progress in obtaining a quantitative understanding of various corners in the space of all possible CFTs.

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Workshop / Seminar Wed, 06 Feb 2019 18:17:05 -0500 2019-02-06T16:00:00-05:00 2019-02-06T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Astronomy Colloquium Series Presents (February 7, 2019 3:30pm) https://events.umich.edu/event/58569 58569-14511743@events.umich.edu Event Begins: Thursday, February 7, 2019 3:30pm
Location: West Hall
Organized By: Department of Astronomy

“Mergers of compact objects in the Gravitational Wave Era”

The observation of gravitational waves has opened a new, unexplored window onto the Universe. Among the sources of gravitational wave transients, compact objects such as neutron stars (NSs) and black holes (BHs) play the most important role. In this talk, I will focus on the expected gravitational wave signal when two compact objects (NS-NS and NS-BH) in a binary merge. These events are believed to be accompanied by a strong electromagnetic signature in gamma-rays, followed by longer-wavelength radiation. I will discuss what can be learned from the complementary observations of the electromagnetic and the gravitational wave signals during these events.

Should you require any reasonable accommodations to ensure equal access and opportunity related to this event, please contact Stacy Tiburzi at 734-764-3440 or stibu@umich.edu.

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Lecture / Discussion Mon, 04 Feb 2019 13:25:04 -0500 2019-02-07T15:30:00-05:00 2019-02-07T16:20:00-05:00 West Hall Department of Astronomy Lecture / Discussion Dr. Rosalba Perna
Statistics Department Seminar Series: Cosma Shalizi, Associate Professor, Department of Statistics, Carnegie Mellon University (February 8, 2019 11:30am) https://events.umich.edu/event/60665 60665-14937147@events.umich.edu Event Begins: Friday, February 8, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

Latent homophily generally makes it impossible to identify contagion or influence effects from observations on social networks. Sometimes, however, homophily also makes it possible to accurately infer nodes' latent attributes from their position in the larger network. I will lay out some assumptions on the network-growth process under which such inferences are good enough that they enable consistent and asymptotically unbiased estimates of the strength of social influence. Time permitting, I will also discuss the prospects for tracing out the "identification possibility frontier" for social contagion.

(Joint work with Edward McFowland III; paper: https://arxiv.org/abs/1607.06565 )

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Workshop / Seminar Sat, 02 Feb 2019 10:36:05 -0500 2019-02-08T11:30:00-05:00 2019-02-08T12:30:00-05:00 West Hall Department of Statistics Workshop / Seminar Cosma Shalizi
HET Seminars | The Search for Axion Dark Matter (February 8, 2019 3:00pm) https://events.umich.edu/event/60740 60740-14961641@events.umich.edu Event Begins: Friday, February 8, 2019 3:00pm
Location: West Hall
Organized By: HET Seminars

Dark matter is the dominant source of matter in our Universe. However, while dark matter dictates the evolution of large-scale astrophysical systems through its gravitational effects, the particle nature of dark matter is unknown. This is despite the significant effort that has gone into the search for particle dark matter over the past decades. In this talk I will review the current status of the search for particle dark matter. I will focus specifically on a dark matter particle candidate called the axion, which is both well-motivated theoretically and also relatively unexplored experimentally. I will outline the near-term program for searching for axion dark matter and show that if this theory is correct, then we will probably know soon.

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Workshop / Seminar Mon, 04 Feb 2019 09:20:37 -0500 2019-02-08T15:00:00-05:00 2019-02-08T16:00:00-05:00 West Hall HET Seminars Workshop / Seminar West Hall
The Michigan Anthropology Colloquia Series: "Cooperation without Submission: The Juris-diction of Significance in Hopi-U.S. Relations" (February 8, 2019 3:00pm) https://events.umich.edu/event/56314 56314-13878513@events.umich.edu Event Begins: Friday, February 8, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

The founding principles of U.S. law regarding Native Americans, first articulated in the 1830s, define them as “domestic dependent nations” who retain powers of self-government but who are also in a “state of pupilage” to the federal government, in a relationship like that of a “ward to its guardian.” This ambiguous status has offered cover for the shifting winds of U.S. political sentiment, leading sometimes to calls for the assimilation of Native peoples, sometimes for their rights to self-determination. Despite these shifts, tribes like the Hopi Nation in Arizona persist in their claims to being sovereign nations who nonetheless enjoy a unique trust relationship with the U.S. Since the 1990s, and passage of laws like Native American Graves Protection and Repatriation Act, this relationship has been executed pursuant to rules requiring “meaningful tribal consultation” whenever U.S. agencies or their grantees propose actions that may impact Native peoples and their resources, particularly those of substantial natural and/or cultural significance. Disagreement persists about meaningful tribal consultation and its efficacies however. This paper deploys insights from indigenous studies, and legal and linguistic anthropology to analyze the details of the consultations I have observed, since 2012, between Hopi Nation officials and their non-native counterparts in the U.S. Forest Service and the Field Museum of Natural History. Unpacking those interactions in light of Hopi theories of knowledge and authority, through a theory of legal language as juris-diction, I argue that these consultations enact Hopi and Anglo-legal norms of “significance” in complex, contradictory ways. I suggest that understanding “meaningful tribal consultation,” and the settler legal status of Native Nations more generally, requires understanding how indigenous nations enact the conditions of their authority through juris-diction and the relations and refusals to settler colonialism this inevitably entails.

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Fri, 25 Jan 2019 09:26:11 -0500 2019-02-08T15:00:00-05:00 2019-02-08T17:00:00-05:00 West Hall Department of Anthropology Lecture / Discussion West Hall
The Search for Axion Dark Matter (February 8, 2019 3:00pm) https://events.umich.edu/event/62642 62642-15416701@events.umich.edu Event Begins: Friday, February 8, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

Dark matter is the dominant source of matter in our Universe. However, while dark matter dictates the evolution of large-scale astrophysical systems through its gravitational effects, the particle nature of dark matter is unknown. This is despite the significant effort that has gone into the search for particle dark matter over the past decades. In this talk I will review the current status of the search for particle dark matter. I will focus specifically on a dark matter particle candidate called the axion, which is both well-motivated theoretically and also relatively unexplored experimentally. I will outline the near-term program for searching for axion dark matter and show that if this theory is correct, then we will probably know soon.

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Lecture / Discussion Wed, 27 Mar 2019 13:36:31 -0400 2019-02-08T15:00:00-05:00 2019-02-08T16:00:00-05:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
Quantitative Biology Seminar | Big Data Methods for EEG Analysis in Epilepsy (February 11, 2019 12:00pm) https://events.umich.edu/event/60969 60969-14999996@events.umich.edu Event Begins: Monday, February 11, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Quantitative Biology Seminar

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Workshop / Seminar Mon, 11 Feb 2019 18:16:50 -0500 2019-02-11T12:00:00-05:00 2019-02-11T13:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | Simulating structure formation in different environments and the application on massive neutrinos (February 11, 2019 4:00pm) https://events.umich.edu/event/58684 58684-14544787@events.umich.edu Event Begins: Monday, February 11, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The observables of the large-scale structure such as galaxy number density generally depends on the density environment (of a few hundred Mpc). The dependence can traditionally be studied by performing gigantic cosmological N-body simulations and measuring the observables in different density environments. Alternatively, we perform the so-called "separate universe simulations", in which the effect of the environment is absorbed into the change of the cosmological parameters. For example, an overdense region is equivalent to a universe with positive curvature, hence the structure formation changes accordingly compared to the region without overdensity. In this talk, I will introduce the "separate universe mapping", and present how the power spectrum and halo mass function change in different density environments, which are equivalent to the squeezed bispectrum and the halo bias, respectively. I will then discuss the extension of this approach to inclusion of additional fluids such as massive neutrinos. This allows us to probe the novel scale dependence of halo bias and squeezed bispectrum caused by massive neutrinos. Finally, I will present a recent confirmation of the neutrino effect on halo bias by a different simulation technique, and discuss the impact on constraining the cosmological parameters.

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Workshop / Seminar Mon, 11 Feb 2019 18:16:49 -0500 2019-02-11T16:00:00-05:00 2019-02-11T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Physics Department DEI Workshop Series | Cuts: Responding to Student Climate Concerns (February 12, 2019 10:30am) https://events.umich.edu/event/60676 60676-14937163@events.umich.edu Event Begins: Tuesday, February 12, 2019 10:30am
Location: West Hall
Organized By: Department of Physics

Though the University of Michigan aspires to cultivate a climate that is welcoming to the members of their diverse student, faculty, and staff bodies, we know that the lived experiences of many in our communities don’t always align with these aspirations. Join the CRLT Players for "Cuts: Responding to Student Climate Concerns" which invites participants to think together about the many forces that can shape campus climate both positively and negatively. Comprised of a series of vignettes focused on a Muslim student over a year as she encounters multiple issues of bias, the sketch depicts how such incidents build up over time to create a negative climate for targeted students. Discussion focuses on exploring the issues, as well as potential responses to them.

This workshop is open to all staff, faculty, and graduate students of the Physics/Applied Physics Department. Please RSVP by clicking the link below by Wednesday, February 6 to attend.

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Workshop / Seminar Mon, 04 Feb 2019 11:26:07 -0500 2019-02-12T10:30:00-05:00 2019-02-12T12:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Thermodynamic Limits far from Equilibrium (February 13, 2019 4:00pm) https://events.umich.edu/event/60395 60395-14875120@events.umich.edu Event Begins: Wednesday, February 13, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Thermodynamics is a remarkably successful theoretical framework, with wide ranging applications across the natural sciences. Unfortunately, thermodynamics is limited to equilibrium or near-equilibrium situations, whereas most of the natural world, especially life, operates very far from thermodynamic equilibrium. Without a robust nonequilibrium thermodynamics, we cannot address a whole host of pressing research questions regarding the energetic requirements to operate outside of equilibrium, like the energetic cost to form a pattern, replicate an organism, or sense an environment, to name a few. Research in nonequilibrium statistical thermodynamics is beginning to shed light on these questions. In this talk, I will present two such recent predictions. The first is a novel linear-response-like bound that quantifies how dissipation shapes fluctuations far from equilibrium. Besides its intrinsic allure as a universal relation, I will discuss how it can be used to probe the energetic efficiency of molecular motors, offer energetic constraints on chemical clocks, and bound the dissipation in complex materials, both biological and synthetic, allowing us to gain insight into the fundamental energetic requirements to operate out of thermodynamic equilibrium. The second is an extended second law of thermodynamics with information that quantifies the precise energetic costs to process information, make a measurement, and implement feedback.

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Workshop / Seminar Wed, 13 Feb 2019 18:16:50 -0500 2019-02-13T16:00:00-05:00 2019-02-13T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Astronomy Colloquium Series Presents (February 14, 2019 3:30pm) https://events.umich.edu/event/58571 58571-14511744@events.umich.edu Event Begins: Thursday, February 14, 2019 3:30pm
Location: West Hall
Organized By: Department of Astronomy

Details to be announced

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Lecture / Discussion Thu, 13 Dec 2018 14:42:20 -0500 2019-02-14T15:30:00-05:00 2019-02-14T16:20:00-05:00 West Hall Department of Astronomy Lecture / Discussion West Hall
Statistics Department Seminar Series: Tonglin Zhang, Associate Professor, Department of Statistics, Purdue University (February 15, 2019 11:30am) https://events.umich.edu/event/60670 60670-14937153@events.umich.edu Event Begins: Friday, February 15, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

Recently, rapid advances in science and technology have brought extraordinary amount of data that cannot be analyzed by traditional statistical or machine learning approaches and algorithms. These advances provide unprecedented opportunities and challenges to tackle much larger and more complicated data in academics and industry. To overcome these difficulties, massive computing frameworks such as MapReduce and Spark are becoming increasingly important. However, statistical challenges have not been paid much attention to in the implementation of these frameworks. Recently, we have proposed to use sufficient statistics instead of the whole data in the analysis. We have investigated the concept of sufficient statistics under the framework of a variety of statistical approaches, including linear regression and generalized linear models. The current talk will focus on linear regression problems. It will briefly mention the idea to generalized linear models.

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Workshop / Seminar Thu, 07 Feb 2019 16:16:41 -0500 2019-02-15T11:30:00-05:00 2019-02-15T12:30:00-05:00 West Hall Department of Statistics Workshop / Seminar Tonglin Zhang
Building bulk observables in AdS/CFT (February 15, 2019 3:00pm) https://events.umich.edu/event/61024 61024-15018180@events.umich.edu Event Begins: Friday, February 15, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

The AdS/CFT correspondence relates a theory of gravity in anti-de Sitter space to a CFT on the boundary. A natural question is how local fields in AdS can be expressed in terms of the CFT. In the 1/N expansion this can be done by (i) identifying suitable building blocks - free bulk fields - in the CFT, (ii) assembling the building blocks to make interacting bulk fields. I'll present an approach where the first step is carried out using modular flow in the CFT and the second step is driven by requiring bulk causality.

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Lecture / Discussion Wed, 27 Mar 2019 13:34:19 -0400 2019-02-15T15:00:00-05:00 2019-02-15T16:00:00-05:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
HET Seminars | Building Bulk Observables in AdS/CFT (February 15, 2019 3:00pm) https://events.umich.edu/event/61036 61036-15024922@events.umich.edu Event Begins: Friday, February 15, 2019 3:00pm
Location: West Hall
Organized By: Department of Physics

The AdS/CFT correspondence relates a theory of gravity in anti-de Sitter space to a CFT on the boundary. A natural question is how local fields in AdS can be expressed in terms of the CFT. In the 1/N expansion this can be done by (i) identifying suitable building blocks - free bulk fields - in the CFT, (ii) assembling the building blocks to make interacting bulk fields. I'll present an approach where the first step is carried out using modular flow in the CFT and the second step is driven by requiring bulk causality.

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Workshop / Seminar Mon, 11 Feb 2019 09:28:30 -0500 2019-02-15T15:00:00-05:00 2019-02-15T16:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
The Michigan Anthropology Colloquia Series: "Figure (of Personhood) Drawing: Pictorial Representations of Signing and Signers in Nepal" (February 15, 2019 3:00pm) https://events.umich.edu/event/51729 51729-12214205@events.umich.edu Event Begins: Friday, February 15, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"Nepali Sign Language (NSL) has primarily been represented in print through pictorial images of signing persons. This talk draws on long-term ethnographic research with Nepali signers to explore the affordances of drawings for representing and generating linguistic form, reference, connotation, and entanglement with other modes of semiosis. I focus specifically on post-Maoist Civil War changes in visual representations of the figures of personhood portrayed performing signs in NSL texts; the role of both drawings and the act of drawing in recent initiatives to include previously marginal elderly novice signers into deaf life; and my own efforts to follow deaf artists in incorporating drawings into my toolkit for recording, analyzing, and sharing representations of signing practices. Across these contexts, how does the production and interpretation of pictorial images function as a resource for creating indexical icons that can performatively call forth new conditions? In addition to analyzing social change among deaf networks in Nepal, this talk shows that ethnographic attention to drawing can contribute to conversations about how linguistic anthropology can forge connections with visual anthropology in order to help our research processes and products embody our commitment to analyzing multimodal total semiotic facts."

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Mon, 07 Jan 2019 09:11:06 -0500 2019-02-15T15:00:00-05:00 2019-02-15T17:00:00-05:00 West Hall Department of Anthropology Lecture / Discussion West Hall
HEP-Astro Seminar | Dark Energy: status and prospects after the 6th and final observing season of DES (February 18, 2019 4:00pm) https://events.umich.edu/event/59061 59061-14677936@events.umich.edu Event Begins: Monday, February 18, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The Dark Energy Survey (DES) is the state-of-the art imaging survey for dark energy. Since its first observing campaign, in 2013, DES has produced many exciting results, including: the most precise cosmological measurements from weak gravitational lensing of 400M galaxies, the first ever observation of the optical transient associated with a gravitational wave emitting astrophysical event (the binary neutron star merger GW1708117), and the first ever measurement of the rate of expansion of the universe using a dark gravitational wave standard siren (the binary black hole merger GW170814). After six years of data taking, on January 9 2019 DES completed its main survey observations. The collaboration now focuses on obtaining the most precise cosmological measurements, and prepare for target of opportunity observations of upcoming gravitational wave events. In this talk, I present an overview of the most exciting science produced by DES so far and discuss the prospects for the next few years before the start of the next-generation survey with the upcoming LSST instrument.

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Workshop / Seminar Mon, 18 Feb 2019 18:16:57 -0500 2019-02-18T16:00:00-05:00 2019-02-18T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Antenna Characterization Using Vapor Cell Rydberg EIT (February 19, 2019 4:00pm) https://events.umich.edu/event/61222 61222-15054305@events.umich.edu Event Begins: Tuesday, February 19, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Atomic detectors for sensing and measurement of AC electric fields show certain advantages over traditional dipole antenna, such as the capability to measure absolute electric field strengths, and a higher physical resolution. Here I will present experimental detection of incident RF fields, using electromagnetically induced transparency (EIT) spectroscopy on Rydberg states within an atomic vapor. The small (5.5 x 5.5 mm cross-section) Rubidium vapor cell is used to image the field the near-field from a microwave horn, to a spatial resolution of lambda/10, covering a field-amplitude range from 50 to 350 V/m. Results are compared to finite-element field simulations, and further experiments demonstrating the ability to record absolute field amplitude and frequency values will be discussed.

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Workshop / Seminar Tue, 19 Feb 2019 18:16:43 -0500 2019-02-19T16:00:00-05:00 2019-02-19T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Collective Physics for Breaking Quantum and Thermal Limits on Precision Measurements (February 20, 2019 4:00pm) https://events.umich.edu/event/61223 61223-15054306@events.umich.edu Event Begins: Wednesday, February 20, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

A long-standing theme of atomic physics is a continual striving to gain ever greater control over single quantum objects, starting with their internal degrees of freedom and now extending to their external degrees of freedom. Having learned to exert nearly complete control over single atoms, what are the new frontiers? One direction is to now exert similar levels of control over the interactions and correlations between atoms, with examples including quantum computing with trapped ions, quantum many-body simulations in degenerate atomic gases, and the deterministic assembly of molecules. Our lab has been asking the question: is it also possible to exploit atom-atom correlations and entanglement to advance the field of precision measurement beyond the single-atom paradigm that dominates the field? Using laser-cooled and trapped rubidium and strontium atoms inside of high finesse optical cavities, we have explored this question along two fronts by surpassing the standard quantum limit on quantum phase estimation by a factor of 60 and overcoming thermal limits on laser frequency stability. If time permits, I will also discuss the emergence of spin-exchange interactions between atoms mediated by the optical cavity. Possible future impacts include robust millihertz linewidth optical lasers, advanced optical lattice clocks, and searches for new physics.

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Workshop / Seminar Wed, 20 Feb 2019 18:16:52 -0500 2019-02-20T16:00:00-05:00 2019-02-20T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
HET Seminars | *To Be Confirmed* (February 21, 2019 12:00pm) https://events.umich.edu/event/61331 61331-15088051@events.umich.edu Event Begins: Thursday, February 21, 2019 12:00pm
Location: West Hall
Organized By: HET Seminars

*To Be Confirmed*

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Lecture / Discussion Mon, 18 Feb 2019 09:39:40 -0500 2019-02-21T12:00:00-05:00 2019-02-21T13:00:00-05:00 West Hall HET Seminars Lecture / Discussion West Hall
Statistics Department Seminar Series: Peter Hoff, Professor, Statistical Science Department, Duke University (February 22, 2019 11:30am) https://events.umich.edu/event/60671 60671-14937154@events.umich.edu Event Begins: Friday, February 22, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

Mixed effects models are used routinely to share information across groups and to account for data dependence. The statistical properties of such models are often quite good on average across groups, but may be poor for any specific group. For example, commonly-used confidence interval procedures may maintain a target coverage rate on average across groups, but
have near zero coverage rate for a group that differs substantially from the others. In this talk, we review some basic mixed effects modeling tools, discuss their group-specific properties, and present some new tools for multiple testing and inference problems that permit information sharing across groups while controlling group-specific frequentist error rates.

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Workshop / Seminar Mon, 11 Feb 2019 15:37:29 -0500 2019-02-22T11:30:00-05:00 2019-02-22T12:30:00-05:00 West Hall Department of Statistics Workshop / Seminar Peter Hoff
The Michigan Anthropology Colloquia Series: "Linguistic Relativity with an Attitude: Navajo place-names and the public sphere" (February 22, 2019 3:00pm) https://events.umich.edu/event/52364 52364-12650103@events.umich.edu Event Begins: Friday, February 22, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"This talk reflects on the controversy on the Navajo Nation of changing the name of Kit Carson Drive to the Navajo place name Tséhootsooí. I outline the structure and use of traditional Navajo place names and then show that Navajo place names have had a renaissance in signage for shopping centers and elsewhere on the Navajo Nation. I then detail the controversy over a proposal to change a street name in Fort Defiance. Place names are not neutral, but fully implicated in concerns about who has and does not have the right (and power) to name. In debates about linguistic relativity, questions of the inequalities of language need to be engaged. This, I argue, is linguistic relativity with an attitude--taken out of the free-floating ahistorical itemizable lexical unit and put back--where it has always been--in the lives of people."

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Thu, 13 Dec 2018 12:02:38 -0500 2019-02-22T15:00:00-05:00 2019-02-22T17:00:00-05:00 West Hall Department of Anthropology Lecture / Discussion West Hall
Leveraging Information Theory to Practical Machine Learning: Minimum Description Length Regularization for Online Learning (February 22, 2019 4:00pm) https://events.umich.edu/event/60992 60992-15000018@events.umich.edu Event Begins: Friday, February 22, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: Classical online learning techniques enforce a prior distribution on the objective to be optimized in order to induce model sparsity. Such prior distributions are chosen with mathematical convenience in mind, but not necessarily for being the best priors. The Minimum Description Length (MDL) principle is usually used with two pass strategies, one for feature selection, and a second one for optimization with the selected features.

An approach inspired by the Minimum Description Length principle is proposed for adaptively selecting and regularizing features during online learning based on their usefulness in improving the objective. The approach eliminates noisy or useless features from the optimization process, leading to improved loss. By utilizing the MDL principle, this approach enables an optimizer to reduce the problem dimensionality to the subspace of the feature space for which the smallest loss is obtained. The approach can be tuned for trading off between model sparsity and accuracy. Empirical results on large scale practical real-world systems demonstrate how it improves such tradeoffs. Huge model size reductions can be achieved with no loss in performance relative to standard techniques, while moderate loss improvements (which can translate to large regret improvements) are achieved with moderate size reductions. The results also demonstrate that overfitting is mitigated by this approach. Analysis shows that the approach can achieve the loss of optimizing with the best feature subset.

Bio: Gil Shamir received the B.Sc. (Cum Laude), and M.Sc. degrees from the Technion, Israel – Institute of Technology, Haifa, Israel in 1990 and 1997, respectively, and the Ph.D. degree from the University of Notre Dame, Notre Dame, IN, U.S.A. in 2000, all in electrical engineering.

From 1990 to 1995 he participated in research and development of signal processing and communication systems. From 1995 to 1997 he was with the Electrical Engineering Department at the Technion – Israel Institute of Technology, as a graduate student and teaching assistant. From 1997 to 2000 he was a Ph.D. student and a research assistant in the Electrical Engineering Department at the University of Notre Dame, and then a post-doctoral fellow until 2001. During his tenure at Notre Dame he was a fellow of the Center for Applied Mathematics of the university. Between 2001 and 2008 he was with the Electrical and Computer Engineering Department at the University of Utah, and between 2008 and 2009 with Seagate Research. Since 2009 he has been with Google. His main research interests include information theory, machine learning, coding and communication theory. Dr. Shamir received an NSF CAREER award in 2003.

For more information on MIDAS or the Seminar Series, please contact midas-contact@umich.edu. MIDAS gratefully acknowledges Wacker Chemie AG for its generous support of the MIDAS Seminar Series.

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Workshop / Seminar Fri, 08 Feb 2019 15:26:46 -0500 2019-02-22T16:00:00-05:00 2019-02-22T17:00:00-05:00 West Hall Michigan Institute for Data Science Workshop / Seminar Gil Shamir, PhD
Department Colloquium | Facilitating Thinking and Learning in and Beyond the Physics Classrooms (February 27, 2019 4:00pm) https://events.umich.edu/event/60564 60564-14910378@events.umich.edu Event Begins: Wednesday, February 27, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

I will discuss, using my research in physics education, how research can be used as a guide to develop curricula and pedagogies to reduce student difficulties. My research has focused on improving student understanding of introductory and advanced concepts, for example, in learning quantum mechanics. We are developing research-based learning tools such as tutorials and peer instruction tools that actively engage students in the learning process. I will discuss how we evaluate their effectiveness using a variety of methodologies. I will also discuss our research studies that provide guidelines for how to enhance physics by making it inclusive.

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Workshop / Seminar Wed, 27 Feb 2019 18:16:16 -0500 2019-02-27T16:00:00-05:00 2019-02-27T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
CM Theory Seminar | The Redefinition of the SI System of Units, and the Single-Electron Ratchet Pump as a Current Standard (February 28, 2019 9:00am) https://events.umich.edu/event/61507 61507-15119364@events.umich.edu Event Begins: Thursday, February 28, 2019 9:00am
Location: West Hall
Organized By: Department of Physics

The Systeme Internationale d’Unites is being redefined, in an interesting way. This redefinition has fundamental implications for electrical standards, including standards of current based on the charge of the electron. One mode of semiconducting single-electron pump is the single-gate ratchet mode, based on the concept of a Brownian motor – this fact makes the mode quite subtle in operation. We show experimentally that, in the same devices, we can demonstrate multiple two-gate pumping modes but not the single-gate mode. We propose three mechanisms to explain the lack of plateaus in the single-gate ratchet mode. Educators/textbook writers: I will also discuss a proposal on how to introduce the new SI to students.

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Workshop / Seminar Thu, 28 Feb 2019 18:16:08 -0500 2019-02-28T09:00:00-05:00 2019-02-28T10:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Alessandro Rinaldo, Professor, Department of Statistics & Data Science, Carnegie Mellon University (March 1, 2019 11:30am) https://events.umich.edu/event/60715 60715-14946089@events.umich.edu Event Begins: Friday, March 1, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

Statistical change-point analysis is concerned with detecting and localizing abrupt changes in the data generating distribution in time series. A long-studied subject with a rich literature, change-point analysis has produced a host of well established methods for statistical inference available to practitioners. These techniques are widely used in diverse applications to address important real life problems, such as security monitoring, neuroimaging, ecological statistics and climate change, medical condition monitoring, sensor networks, risk assessment for disease outbreak, genetics and many others. The current frameworks for statistical analysis of change-point problems often times rely on traditional modeling assumptions of parametric nature that are inadequate to capture the inherent complexity of modern, high-dimensional datasets. in this talk I will introduce three high-dimensional change-point localization problems assuming independent observations: for univariate means, covariances and sparse network models. In each case, I will describe a phase transition in the space of the model parameters that sharply separates parameter combinations for which the localization task is possible from the ones for which no consistent estimator of the change-points exists. I will then present the corresponding algorithms for localization, which yield nearly minimax optimal rates in all cases. I will finally discuss ongoing work on a fully non-parametric change-point problem.

Joint work with Daren Wang, Yi Yu and Oscar Hernan Madrid Padilla.

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Workshop / Seminar Sun, 24 Feb 2019 09:05:34 -0500 2019-03-01T11:30:00-05:00 2019-03-01T12:30:00-05:00 West Hall Department of Statistics Workshop / Seminar Alessandro Rinaldo
Matrix Completion in Network Analysis (March 1, 2019 4:00pm) https://events.umich.edu/event/61639 61639-15161279@events.umich.edu Event Begins: Friday, March 1, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: Matrix completion is an active area of research in itself,and a natural tool to apply to network data, since many real networks are observed incompletely and/or with noise. However, developing matrix completion algorithms for networks requires taking into account the network structure. This talk will discuss three examples of matrix completion used for network tasks. First, we discuss the use of matrix completion for cross-validation or non-parametric bootstrap on network data, a long-standing problem in network analysis. Two other examples focus on reconstructing incompletely observed networks, with structured missingness resulting from network sampling mechanisms. One scenario we consider is egocentric sampling, where a set of nodes is selected first and then their connections to the entire network are observed. Another scenario focuses on data from surveys, where people are asked to name a given number of friends. We show that matrix completion can generally be very helpful in solving network problems, as long as the network structure is taken into account. This talk is based on joint work with Elizaveta Levina, Tianxi Li and Yun-Jhong Wu.

Bio: Ji Zhu is a Professor in the Department of Statistics at the University of Michigan, Ann Arbor. He received his B.Sc. in Physics from Peking University, China in 1996 and M.Sc. and Ph.D. in Statistics from Stanford University in 2000 and 2003, respectively. His primary research interests include statistical machine learning, high-dimensional data modeling, statistical network analysis and their applications to health sciences. He received an NSF CAREER Award in 2008; and he was elected as a Fellow of the American Statistical Association in 2013 and a Fellow of the Institute of Mathematical Statistics in 2015.

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Workshop / Seminar Tue, 26 Feb 2019 13:51:23 -0500 2019-03-01T16:00:00-05:00 2019-03-01T17:00:00-05:00 West Hall Michigan Institute for Data Science Workshop / Seminar Ji Zhu, PhD
Quantitative Biology Seminar | Understanding Entrainment Properties of Circadian Oscillator Models Using a One-dimensional Map (March 11, 2019 12:00pm) https://events.umich.edu/event/59063 59063-14677938@events.umich.edu Event Begins: Monday, March 11, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

A central feature of many oscillatory networks is their ability to display phase-locked solutions where the constituent elements fall into a well-defined pattern in which the phase difference between pairs of oscillators can be determined. Often the networks contain an identifiable pacemaker or external forcing. In these cases, the network is said to be entrained, because the pacemaker determines the overall network period and phasing. In this talk, we consider entrainment that arises in circadian systems. Such networks are subject to an external, pacemaking 24 hour light-dark drive in which the intensity and total hours of light within the 24 hour cycle are important parameters. We will introduce a new computational tool, a 1-dimensional entrainment map, to assess whether and at what phase a circadian oscillator entrains to periodic light-dark (LD) forcing. We have applied the map to a variety of circadian oscillators ranging from the Novak-Tyson model for protein-mRNA interactions to the Kronauer model of the human circadian rhythm. Using the entrainment map, we systematically investigate how various intrinsic properties of the circadian oscillator interact with properties of the LD forcing to produce stable circadian rhythms. We will focus on how to use the map to study the reentrainment process due long-distance travel to address the so-called east-west asymmetry of jet lag. Further, we show that individuals can experience jet lag after purely north-south travel. The mathematical and computational methods used to study these problems should be of wide interest to members of the mathematics community.

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Workshop / Seminar Mon, 11 Mar 2019 18:16:08 -0400 2019-03-11T12:00:00-04:00 2019-03-11T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro | Probing the non-Gaussian density field with clusters of galaxies (March 11, 2019 4:00pm) https://events.umich.edu/event/61833 61833-15215047@events.umich.edu Event Begins: Monday, March 11, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Considerable effort in cosmology today is focused on understanding the statistical nature and evolution of the (dark matter) density field that underlies the observed large-scale structure. Information about this field is mostly phrased in terms of two-point statistics, such as the power spectrum of galaxies or weak lensing, essentially approximating the large-scale structure as a Gaussian random field. However, the Universe is far more complex than that: Gravitational collapse turns the simple initial conditions into the cosmic web consisting of halos, filaments and large voids we see today. In my talk, I will show how we can use the abundance of galaxy clusters residing in the the 'knots' of the cosmic web to probe the non-Gaussian shape of the density field. This gives us insights into the physics of structure formation, and provides at the same time a new method to search for deviations from the cosmological standard model.

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Workshop / Seminar Mon, 11 Mar 2019 18:16:08 -0400 2019-03-11T16:00:00-04:00 2019-03-11T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Building Quantum Materials Out of Light (March 12, 2019 4:00pm) https://events.umich.edu/event/61898 61898-15232577@events.umich.edu Event Begins: Tuesday, March 12, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Can quantum materials be built out of light? In the hope of doing just that, we have developed a system for turning optical photons into cavity Rydberg polaritons: quasiparticles which inherit their spatial waveforms from the modes of an optical cavity and gain strong interactions from Rydberg excitations of an atomic gas. In a single cavity mode, the strong interactions between polaritons manifest as transport blockade, in which an individual photon in the cavity prevents any other photons from entering. To go beyond blockade, we use Floquet engineering to enable the polaritons to move around and self-organize among multiple transverse modes of the cavity. Finally, I will discuss our preliminary experiments on building photonic Laughlin states, the ground states of a fractional quantum Hall system.


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Workshop / Seminar Tue, 12 Mar 2019 18:16:06 -0400 2019-03-12T16:00:00-04:00 2019-03-12T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Creating an Anti-Universe in a Bottle: Fundamental Physics with Trapped Antihydrogen Atoms (March 13, 2019 4:00pm) https://events.umich.edu/event/61264 61264-15063347@events.umich.edu Event Begins: Wednesday, March 13, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The existence of antimatter was first predicted by Dirac in 1928. The antielectron (now called the positron) and the antiproton were discovered experimentally in 1932 and 1955, respectively. It then took, however, more than half a century before physicists were able to create and control the atomic form of antimatter, the antihydrogen atom, in sufficient quantity to be able to study its properties.

The hydrogen atom, the simplest atomic system has played a central role in developments of modern physics. By studying antihydrogen, an antiproton orbited by an antielectron, we wish to precisely probe the fundamental symmetries between matter and antimatter. In particular, CPT (charge, parity, time-reversal) symmetry underpins relativistic quantum field theory, and the Equivalence Principle is a key assumption in Einstein’s General Relativity. A violation of these symmetries, even at a very minute level, would force a radical change in the way we understand subatomic physics at its deepest level. In this talk, I will discuss how we produce, control, and perform precision measurements on antihydrogen atoms that are "bottled" in the ALPHA antihydrogen trap at CERN.

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Workshop / Seminar Wed, 13 Mar 2019 18:16:10 -0400 2019-03-13T16:00:00-04:00 2019-03-13T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Ji Zhu, Professor, Department of Statistics, University of Michigan (March 15, 2019 11:30am) https://events.umich.edu/event/60716 60716-14946090@events.umich.edu Event Begins: Friday, March 15, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

Matrix completion is an active area of research in itself, and a natural tool to apply to network data, since many real networks are observed incompletely and/or with noise. However, developing matrix completion algorithms for networks requires taking into account the network structure. This talk will discuss three examples of matrix completion used for network tasks. First, we discuss the use of matrix completion for cross-validation or non-parametric bootstrap on network data, a long-standing problem in network analysis. Two other examples focus on reconstructing incompletely observed networks, with structured missingness resulting from network sampling mechanisms. One scenario we consider is egocentric sampling, where a set of nodes is selected first and then their connections to the entire network are observed. Another scenario focuses on data from surveys, where people are asked to name a given number of friends. We show that matrix completion can generally be very helpful in solving network problems, as long as the network structure is taken into account.

This talk is based on joint work with Elizaveta Levina, Tianxi Li and Yun-Jhong Wu.

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Workshop / Seminar Wed, 06 Mar 2019 10:21:14 -0500 2019-03-15T11:30:00-04:00 2019-03-15T12:30:00-04:00 West Hall Department of Statistics Workshop / Seminar Ji Zhu
Life After Graduate School Seminar (March 15, 2019 12:00pm) https://events.umich.edu/event/62064 62064-15284707@events.umich.edu Event Begins: Friday, March 15, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Dan will discuss his work at STATS: a leading sports analytics company, as well as his preparation for a career path in Industry.

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Workshop / Seminar Fri, 15 Mar 2019 18:16:36 -0400 2019-03-15T12:00:00-04:00 2019-03-15T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HET Seminars | New Directions in Self-Interacting Dark Matter, From Astrophysics to the Lattice (March 15, 2019 3:00pm) https://events.umich.edu/event/62008 62008-15273941@events.umich.edu Event Begins: Friday, March 15, 2019 3:00pm
Location: West Hall
Organized By: HET Seminars

Dark matter may have its own dark forces and interactions that are distinct from the Standard Model and unrelated the weak scale. To test this idea, galaxies and clusters of galaxies serve as cosmic colliders for measuring self-scattering among dark matter particles. Present constraints imply that if self-interactions are to solve the infamous core-cusp problem in dwarf galaxies, the scattering cross section must fall with energy/velocity to avoid cluster limits. To test this velocity dependence, I present new constraints on dark matter self-interactions at an intermediate scale with groups of galaxies. I also describe using mock observations from N-body simulations of self-interacting dark matter with baryons as a test of our methods. Lastly, I describe some recent work toward strongly-coupled theories of self-interacting dark matter, using tools borrowed from lattice QCD to compute its properties nonperturbatively.

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Workshop / Seminar Mon, 11 Mar 2019 09:00:46 -0400 2019-03-15T15:00:00-04:00 2019-03-15T16:00:00-04:00 West Hall HET Seminars Workshop / Seminar West Hall
New directions in self-interacting dark matter, from astrophysics to the lattice (March 15, 2019 3:00pm) https://events.umich.edu/event/62034 62034-15276115@events.umich.edu Event Begins: Friday, March 15, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

Dark matter may have its own dark forces and interactions that are distinct from the Standard Model and unrelated the weak scale. To test this idea, galaxies and clusters of galaxies serve as cosmic colliders for measuring self-scattering among dark matter particles. Present constraints imply that if self-interactions are to solve the infamous core-cusp problem in dwarf galaxies, the scattering cross section must fall with energy/velocity to avoid cluster limits. To test this velocity dependence, I present new constraints on dark matter self-interactions at an intermediate scale with groups of galaxies. I also describe using mock observations from N-body simulations of self-interacting dark matter with baryons as a test of our methods. Lastly, I describe some recent work toward strongly-coupled theories of self-interacting dark matter, using tools borrowed from lattice QCD to compute its properties nonperturbatively.

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Lecture / Discussion Mon, 11 Mar 2019 14:46:04 -0400 2019-03-15T15:00:00-04:00 2019-03-15T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
Infusing Structure into Machine Learning Algorithms (March 15, 2019 4:00pm) https://events.umich.edu/event/61941 61941-15241347@events.umich.edu Event Begins: Friday, March 15, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: Standard deep-learning algorithms are based on a function-fitting approach that do not exploit any domain knowledge or constraints. This makes them unsuitable in applications that have limited data or require safety or stability guarantees, such as robotics. By infusing structure and physics into deep-learning algorithms, we can overcome these limitations. There are several ways to do this. For instance, we use tensorized neural networks to encode multidimensional data and higher-order correlations. We combine symbolic expressions with numerical data to learn a domain of functions and obtain strong generalization. We combine baseline controllers with learnt residual dynamics to improve landing of quadrotor drones. These instances demonstrate that building structure into ML algorithms can lead to significant gains.

Bio: Anima Anandkumar is a Bren professor at Caltech CMS department and a director of machine learning research at NVIDIA. Her research spans both theoretical and practical aspects of large-scale machine learning. In particular, she has spearheaded research in tensor-algebraic methods, non-convex optimization, probabilistic models and deep learning.
Anima is the recipient of several awards and honors such as the Bren named chair professorship at Caltech, Alfred. P. Sloan Fellowship, Young investigator awards from the Air Force and Army research offices, Faculty fellowships from Microsoft, Google and Adobe, and several best paper awards. She is a member of the World Economic Forum's Expert Network consisting of leading experts from academia, business, government, and the media. She has been featured in documentaries by PBS, KPCC, wired magazine, and in articles by MIT Technology review, Forbes, Yourstory, O’Reilly media, and so on.
Anima received her B.Tech in Electrical Engineering from IIT Madras in 2004 and her PhD from Cornell University in 2009. She was a postdoctoral researcher at MIT from 2009 to 2010, a visiting researcher at Microsoft Research New England in 2012 and 2014, an assistant professor at U.C. Irvine between 2010 and 2016, an associate professor at U.C. Irvine between 2016 and 2017 and a principal scientist at Amazon Web Services between 2016 and 2018.

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Workshop / Seminar Thu, 07 Mar 2019 13:32:47 -0500 2019-03-15T16:00:00-04:00 2019-03-15T17:00:00-04:00 West Hall Michigan Institute for Data Science Workshop / Seminar Animashree Anandkumar, PhD
HEP-Astro Seminar | The Role of Large Volume Neutrino Telescopes in Probing Flavour Oscillations (March 18, 2019 4:00pm) https://events.umich.edu/event/62108 62108-15293419@events.umich.edu Event Begins: Monday, March 18, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Neutrino flavour oscillations are now quite well established, having being probed at different neutrino energies from a few MeV to tens of GeV. In this talk I will focus on the high energy part, highlighting the role of large volume neutrino telescopes in the measurement of flavour oscillation parameters. I will comment on the results of a recent global fit, mentioning the expected contribution of future neutrino telescopes such as ORCA and PINGU. Finally, I will briefly comment on the role of large volume neutrino telescopes to probe some new physics scenarios through flavour oscillations.

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Workshop / Seminar Mon, 18 Mar 2019 18:16:18 -0400 2019-03-18T16:00:00-04:00 2019-03-18T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | "Spintronic" Quantum Transport, Chemistry and Interferometry in an atomic BEC (March 19, 2019 4:00pm) https://events.umich.edu/event/62109 62109-15293420@events.umich.edu Event Begins: Tuesday, March 19, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

In this talk, I will describe our experiments studying spin-dependent quantum transport, chemistry and interferometry in a Bose-Einstein condensate (BEC) of ultracold (87Rb) atoms subject to optically-generated “synthetic” spin-orbit coupling (SOC). We demonstrate spin-resolved atomic beam splitters and two-pathway interferometers based on tunable Landau-Zener transitions in the energy-momentum space (synthetic band structures generated by the SOC as well as Floquet-engineering) [1]. We also demonstrate a new approach of quantum control of (photo) chemical reactions (photoassociation of molecules from atoms) --- a “quantum chemistry interferometry” --- by preparing reactants in (spin) quantum superposition states and interfering multiple reaction pathways [2]. By performing a “quantum quench” in a SOC BEC, we induce head-on collisions between two spinor BECs and study spin transport and how it is affected by SOC, revealing rich phenomena arising from the interplay between quantum interference and many-body interactions [3]. Time permitting, I may discuss our recent realization of a (bosonic) topological state with band crossings protected by nonsymmorphic symmetry [4], by creating a “synthetic” cylinder with combined physical and synthetic dimensions and also a synthetic radial magnetic flux, where the BEC acquires an emergent crystalline order and exhibits quantum transport (Bloch oscillations) mimicking motion on a Mobius strip in energy-momentum space (band structure). Our experimental system can be a rich playground to study physics of interests to AMO physics, quantum chemistry, condensed matter physics, and even high energy physics.

Refs:
[1] A. Olson et al., “Tunable Landau-Zener transitions in a spin-orbit coupled Bose-Einstein condensate”, Phys. Rev. A. 90, 013616 (2014); “Stueckelberg interferometry using periodically driven spin-orbit-coupled Bose-Einstein condensates”, Phys. Rev. A. 95, 043623 (2017)
[2] D. Blasing et al., “Observation of Quantum Interference and Coherent Control in a Photo-Chemical Reaction”, Phys. Rev. Lett. 121, 073202 (2018)
[3] C. Li et al., “Spin Current Generation and Relaxation in a Quenched Spin-Orbit Coupled Bose-Einstein Condensate”, Nature Communications 10, 375 (2019)
[4] C. Li et al., “A Bose-Einstein Condensate on a Synthetic Hall Cylinder”, arXiv: 1809.02122

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Workshop / Seminar Tue, 19 Mar 2019 18:16:21 -0400 2019-03-19T16:00:00-04:00 2019-03-19T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
OS Info Night (March 19, 2019 5:30pm) https://events.umich.edu/event/61168 61168-15045289@events.umich.edu Event Begins: Tuesday, March 19, 2019 5:30pm
Location: West Hall
Organized By: Organizational Studies Program (OS)

Want to learn more about Organizational Studies?

Join us to hear more about this interdisciplinary major based in social sciences where students customize their own education. Enjoy a small community of dedicated and ambitious students with access to top-notch faculty and an engaged alumni network. You'll have the opportunity to hear from the Program Director, Major Advisor, Prospective Student Advisors, and a diverse panel of OS students!

Visit our website in the meantime for more information on the curriculum, application, or to sign-up for a prospective student advising meeting.

Follow us on Facebook to engage with our community and stay up-to-date with OS happenings!

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Meeting Wed, 13 Feb 2019 14:42:53 -0500 2019-03-19T17:30:00-04:00 2019-03-19T19:00:00-04:00 West Hall Organizational Studies Program (OS) Meeting Organizational Studies
Dissertation Defense: Enhancing Prediction Efficacy with High-Dimensional Input Via Structural Mixture Modeling of Local Linear Mapping (March 20, 2019 11:00am) https://events.umich.edu/event/62194 62194-15311061@events.umich.edu Event Begins: Wednesday, March 20, 2019 11:00am
Location: West Hall
Organized By: Department of Statistics

Regression is a widely used statistical tool to discover associations between variables. The estimated relationship can be further utilized for predicting new observations. Obtaining reliable prediction outcomes is a challenging task. When building a regression model, several difficulties such as high dimensionality in predictors, non-linearity of the associations and the unreliable results caused by outliers could deteriorate the results. Furthermore, the prediction error increases if the newly acquired data might not be processed carefully. In this dissertation, we aim at improving prediction performance by enhancing the model robustness at the training stage and duly handling the query data at the testing stage. We propose two methods to build robust models. One focuses on adopting a parsimonious model to limit the number of parameters and a refinement technique to enhance model robustness. We design the procedure to be carried out on parallel systems and further extend their abilities of handling complex and large-scale datasets. The other method restricts the parameter space to avoid the singularity issue and takes up the trimming techniques to limit the influence of outlying observations. We build both approaches by using the mixture-modeling principle to accommodating data heterogeneity without uncontrollably increasing model complexity. Both methods show their abilities to improve prediction performance, compared to existing approaches, in applications such as magnetic resonance vascular fingerprinting and source separation in single-channel polyphonic music, among others. To evaluate model robustness, we develop an efficient approach to generating adversarial samples, which could induce large prediction errors yet are difficult to detect visually. Finally, we propose a preprocessing system to detect and repair different kinds of abnormal testing samples for prediction efficacy, when testing samples are either corrupted or adversarially perturbed.

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Other Tue, 16 Jul 2019 14:26:50 -0400 2019-03-20T11:00:00-04:00 2019-03-20T13:00:00-04:00 West Hall Department of Statistics Other West Hall
Department Colloquium | Universality Classes in the Evolutionary Dynamics of Expanding Populations (March 20, 2019 4:00pm) https://events.umich.edu/event/62045 62045-15278272@events.umich.edu Event Begins: Wednesday, March 20, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Reaction-diffusion waves describe diverse natural phenomena from crystal growth in physics to range expansions in biology. Two classes of waves are known: pulled, driven by the leading edge, and pushed, driven by the bulk of the wave. Recently, we examined how demographic fluctuations change as the density-dependence of growth or dispersal dynamics is tuned to transition from pulled to pushed waves. We found three regimes with the variance of the fluctuations decreasing inversely with the population size, as a power law, or logarithmically. These scalings reflect distinct genealogical structures of the expanding population, which change from the Kingman coalescent in pushed waves to the Bolthausen-Sznitman coalescent in pulled waves. The genealogies and the scaling exponents are model-independent and are fully determined by the ratio of the wave velocity to the geometric mean of dispersal and growth rates at the leading edge. Our theory predicts that positive density dependence in growth or dispersal could dramatically alter evolution in expanding populations even when its contribution to the expansion velocity is small. On a technical side, our work highlights potential pitfalls in the commonly-used method to approximate stochastic dynamics and shows how to avoid them.

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Workshop / Seminar Wed, 20 Mar 2019 18:16:20 -0400 2019-03-20T16:00:00-04:00 2019-03-20T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Chao Gao, Assistant Professor, Department of Statistics, University of Chicago (March 22, 2019 11:30am) https://events.umich.edu/event/60714 60714-14943868@events.umich.edu Event Begins: Friday, March 22, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

I will discuss the problem of statistical estimation with contaminated data. In the first part of the talk, I will discuss depth-based approaches that achieve minimax rates in various problems. In general, the minimax rate of a given problem with contamination consists of two terms: the statistical complexity without contamination, and the contamination effect in the form of modulus of continuity. In the second part of the talk, I will discuss computational challenges of these depth-based estimators. An interesting relation between statistical depth function and a general f-learning framework will be discussed, which leads to a computation strategy via minimax optimization in the framework of generative adversarial nets (GAN). Finally, I will address the problem of adaptive estimation under contamination model. It turns out adaptive estimation becomes a much harder task with contamination. Besides the classical logarithmic cost of adaptive estimation in some cases, it can be shown that in certain situation, adaptation can be completely impossible with any rate.

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Workshop / Seminar Sat, 02 Feb 2019 11:42:29 -0500 2019-03-22T11:30:00-04:00 2019-03-22T12:30:00-04:00 West Hall Department of Statistics Workshop / Seminar Chao Gao
Quantitative Biology Seminar | Pattern Formation and Self-organization in Biological Flows (March 25, 2019 12:00pm) https://events.umich.edu/event/60565 60565-14910379@events.umich.edu Event Begins: Monday, March 25, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Complex life above a certain size would not be possible without a circulatory system. Both plants and animals have developed vascular systems of striking complexity to solve the problem of nutrient delivery, waste removal, and information exchange. Vascular networks are intimately linked to the fitness of organisms. Despite their importance, the principles that govern the structure, topology, function, development and evolution of biological flow networks are not well understood.

In this talk we present how a biological transport network can utilise principles of self organization to develop and function. We first discuss how a hierarchically organized vascular system can develop under constant or variable flow and show how time-dependent flow can stabilize anastomoses and lead to a topology dominated by cycles. Next, inspired by haemodynamic fluctuations in the brain, we examine how networks can produce self-sustained oscillations in the flow even in the absence of varying external input. We discuss how these spontaneously emerging, self-organized fluctuations depend on the network topology, and how they can be modified by a controlled external input.

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Workshop / Seminar Mon, 25 Mar 2019 18:16:13 -0400 2019-03-25T12:00:00-04:00 2019-03-25T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | Future High Energy Electron Accelerators for Particle Physics (March 25, 2019 4:00pm) https://events.umich.edu/event/61834 61834-15215048@events.umich.edu Event Begins: Monday, March 25, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The discovery of a Higgs boson at Europe's Large Hadron Collider (LHC) in 2012 was a major achievement in particle physics. Experimental efforts are ongoing to confirm that it is the Higgs boson predicted by the Standard Model of elementary particle physics and to probe signs for new physics beyond the Standard Model. More importantly, physicists wish to build new powerful particle colliders to fully study this unusual particle, in order to probe the nature, and to attempt to discover new physics. The colloquium will present initiatives for new, large-scale accelerators that include the International Linear Collider (ILC) in Japan, the Compact Linear Collider (CLIC) in Europe, the Circular Electron Positron Collider (CEPC) in China, and Future Circular Collider (FCC) in Europe, all designed to study the Higgs boson in detail or to go beyond in energy the current LHC for particle physics in the energy frontier.

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Workshop / Seminar Fri, 22 Mar 2019 06:16:16 -0400 2019-03-25T16:00:00-04:00 2019-03-25T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Gravitational Wave Detection and Dark Matter Searches with Atom Interferometry (March 26, 2019 4:00pm) https://events.umich.edu/event/62352 62352-15355252@events.umich.edu Event Begins: Tuesday, March 26, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Atom interferometers exploit the quantum mechanical, wavelike nature of massive particles to make a broad range of highly precise measurements. Recent technological advances have opened a path for atom interferometers to contribute to two areas at the forefront of modern physics: gravitational wave astronomy and the search for dark matter. In this seminar, I will describe a new experiment, MAGIS 100, that will use a 100-meter-tall atom interferometer to pursue these directions. MAGIS-100 will serve as a prototype gravitational wave detector in the mid-band frequency range 0.1 Hz to 10 Hz, which is complementary to the frequency bands addressed by laser interferometers such as LIGO and the planned LISA experiment. I will discuss the scientific motivation for gravitational wave detection in the mid-band. In addition, I will explain how MAGIS-100 can look for ultralight dark matter, a well-motivated class of dark matter candidates that behave as coherently oscillating fields.

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Workshop / Seminar Tue, 26 Mar 2019 18:16:13 -0400 2019-03-26T16:00:00-04:00 2019-03-26T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Dark Matter In and Out of Equilibrium (March 29, 2019 3:00pm) https://events.umich.edu/event/62492 62492-15372959@events.umich.edu Event Begins: Friday, March 29, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

One generic scenario for the dark matter of our universe is that it resides in a hidden sector: it talks to other dark fields more strongly than it talks to the Standard Model. I'll discuss some simple, WIMP-y models of this kind of hidden sector dark matter, paying particular attention to what we can learn from the cosmic history of the dark sector. In particular, the need to populate the dark sector in the early universe can control the observability of dark matter today. Some results of interest include new cosmological lower bounds on direct detection cross-sections and simple models of dark matter with parametrically novel behavior.

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Lecture / Discussion Fri, 22 Mar 2019 14:22:54 -0400 2019-03-29T15:00:00-04:00 2019-03-29T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
HET Seminars | Dark Matter In and Out of Equilibrium (March 29, 2019 3:00pm) https://events.umich.edu/event/62524 62524-15397101@events.umich.edu Event Begins: Friday, March 29, 2019 3:00pm
Location: West Hall
Organized By: HET Seminars

One generic scenario for the dark matter of our universe is that it resides in a hidden sector: it talks to other dark fields more strongly than it talks to the Standard Model. I'll discuss some simple, WIMP-y models of this kind of hidden sector dark matter, paying particular attention to what we can learn from the cosmic history of the dark sector. In particular, the need to populate the dark sector in the early universe can control the observability of dark matter today. Some results of interest include new cosmological lower bounds on direct detection cross-sections and simple models of dark matter with parametrically novel behavior.

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Workshop / Seminar Mon, 25 Mar 2019 09:06:43 -0400 2019-03-29T15:00:00-04:00 2019-03-29T16:00:00-04:00 West Hall HET Seminars Workshop / Seminar West Hall
PIMKIO 7 (March 30, 2019 9:00am) https://events.umich.edu/event/62753 62753-15460049@events.umich.edu Event Begins: Saturday, March 30, 2019 9:00am
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

Partice physics in Michigan, Indiana, Kentucky, Illinois and Ohio.

This meeting will bring together the local community of midwest phenomenologists to share their work and discuss recent advances in high energy particle physics, particle astrophysics, dark matter, and cosmology.

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Workshop / Seminar Mon, 01 Apr 2019 13:59:20 -0400 2019-03-30T09:00:00-04:00 2019-03-30T17:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Workshop / Seminar West Hall
the 7th LCTP Spring Symposium (April 1, 2019 8:00am) https://events.umich.edu/event/62752 62752-15460046@events.umich.edu Event Begins: Monday, April 1, 2019 8:00am
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

In the 7th Annual LCTP Spring Symposium, the main focus will be set on Neutrino Physics, with numerous speakers covering the field.

Event program can be found in the Symposium Program link below.

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Workshop / Seminar Mon, 26 Aug 2019 10:49:31 -0400 2019-04-01T08:00:00-04:00 2019-04-01T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Workshop / Seminar West Hall
Dissertation Defense: Approaches for identifying biases in single-cell RNA-sequencing data (April 1, 2019 12:00pm) https://events.umich.edu/event/62523 62523-15397100@events.umich.edu Event Begins: Monday, April 1, 2019 12:00pm
Location: West Hall
Organized By: Department of Statistics

Single-cell RNA-sequencing (scRNA-seq) involves the measurement of gene expression from isolated single cells, with the potential to illuminate cellular heterogeneity within complex tissue samples. However, scRNA-seq data are subject to a large number of technical effects. In this work, we present two approaches that can be applied for removing technical effects from scRNA-seq data in downstream analyses. The first part introduces different concepts of stably expressed genes with respect to true biological expression. Different classes of stably expressed genes may capture different technical effects, assisting in the removal of these technical effects and increasing the biological interpretability of later results. We find that genes associated with the cytosolic ribosomal structure of cells are enriched with genes that are stably expressed in proportion to the total RNA content of a cell. The cytosolic ribosomal genes can serve as a foundation for a gene set incorporated into normalization procedures to remove some technical effects associated with cell size. The second part describes a procedure to analyze which genes are captured with more accuracy from scRNA-seq experiments. The number of reads captured for each unique molecular identifier (UMI) informs how well a specific gene is captured within a dataset. Reliably detectable genes can then be applied to downstream analyses, correcting for additional technical effects. Together, these two projects provide two approaches to identifying genes that capture technical effects in scRNA-seq data and can be applied to later normalization procedures.

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Other Tue, 16 Jul 2019 14:26:14 -0400 2019-04-01T12:00:00-04:00 2019-04-01T14:00:00-04:00 West Hall Department of Statistics Other flyer
The Michigan Anthropology Colloquia Series: "Lemnian Earth and Foreign Forms: ceramics at Koukonissi in the Late Bronze Age" (April 1, 2019 3:00pm) https://events.umich.edu/event/51872 51872-12274522@events.umich.edu Event Begins: Monday, April 1, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"Only a short distance offshore from Troy, the Bronze Age settlement on the islet of Koukonissi, Lemnos offers important evidence for the local production and consumption of Mycenaean pottery during the 14th century BCE, a time ostensibly of little contact of the North Aegean with the Mycenaean world, with the best evidence for Mountjoy’s “Upper Interface” being represented by Troy (phase VI late). This paper presents new evidence produced by integrated petrographic, chemical and stylistic ceramic analysis for Koukonissi as an outpost of the Southern Aegean, and contrasts this with its neighbor Troy on the Asia Minor coast.

At Troy during LH IIIA2, the bulk of the Mycenaean pottery seems to have been imported, mainly from the Argolid/NE Peloponnese, with assumed local pattern painted wares comprising only a small part of the total assemblage and standard Mycenaean wares (fine plain) being rare. In contrast, typical Mycenaean shapes were commonly imitated at Troy in local fabrics (grey and tan wares).

At Koukonissi, standard Mycenaean pottery, such as fine plain wares, are locally produced and well represented. Most importantly, the common local ware (Red Slipped pottery) seems relatively unaffected by the Mycenaean repertoire. This lies in contrast to other parts of the Eastern Aegean and Troy, where hybrid shapes and decorations are present.

This new identification of previously undocumented, substantial production of Mycenaean pottery on Lemnos has far-reaching implications, as some of the Eastern Aegean Mycenaean chemical compositional groups may have been produced on the island, something quite unexpected. The evidence from Koukonissi, therefore, offers the potential to alter our view of the interface between Mycenaean and other cultures. It suggests the existence of important differences at a social, economic and cultural level between Troy and Koukonissi, and a diversity of interaction with the southern Aegean and Mycenaean Greece between different sites in the North Aegean."




Mini-Bio:

Peter Day teaches and researches in the Department of Archaeology at the University of Sheffield, running a research group on ceramics which has close ties with the the National Centre for Scientific Research ‘Demokritos’ in Greece and the University of Barcelona.

He gained his BA in Archaeology at the University of Southampton under Colin Renfrew and Peter Ucko as Heads of Department. Having trained in Ceramic Petrography with David Peacock, he worked as Research Fellow in Ceramic Petrology at the Fitch Laboratory, British School at Athens from 1984-1986. He subsequently carried out doctoral research in the Department of Archaeology, University of Cambridge, under the supervision of Sander van der Leeuw, on ceramic production in East Crete during the Neopalatial period of the Bronze Age and the twentieth century. He held a Postdoctoral Fellowship at Cambridge before a two year postdoctoral position at NCSR ‘Demokritos from 1991-1993.

From 1994 he has been based in Sheffield, working on analytical approaches to ceramics, both in terms of provenance and especially the reconstruction of ceramic technologies. From 1998-2002, he was Co-ordinator of the GEOPRO European Training Network and has been involved in a succession of other major, collaborative projects funded by the European Union. His research usually has a Mediterranean focus, though he has also been involved in a range of ceramic-based projects in Asia, Africa and the Americas. Although basically an anthropological archaeologist and prehistorian, Peter has been gradually civilized by a number of postgraduates and postdoctoral researchers that he has had the privilege of working with.

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Wed, 27 Mar 2019 10:30:24 -0400 2019-04-01T15:00:00-04:00 2019-04-01T17:00:00-04:00 West Hall Department of Anthropology Lecture / Discussion West Hall
HEP-Astro Seminar | Physics and astrophysics at DUNE: a theorist's perspective (April 1, 2019 4:00pm) https://events.umich.edu/event/62586 62586-15407988@events.umich.edu Event Begins: Monday, April 1, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Deep Underground Neutrino Experiment, which is being actively developed by an international collaboration of 1,000+ researchers from 30+ countries, will be a multi-decade physics program. The experiment will carry out precision oscillation measurements in the neutrino beam created at Fermilab, look for nucleon decay, and be ready to capture a burst of neutrinos from a galactic core-collapse supernova. Theoretical input is essential for many aspects of this program. In the first part of the talk, I will discuss some relevant aspects of the neutrino-nucleus cross section physics and related questions about measuring neutrino energy at DUNE. In the second part, I will focus on the astrophysical capabilities of the far detector. I will show that the supernova burst signal carries in it the signatures of physical processes taking place close to the collapsed core. If we know what to look for, we can learn about the conditions in the neutrino-driven wind and the impact of collective flavor oscillations.

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Workshop / Seminar Mon, 01 Apr 2019 18:16:10 -0400 2019-04-01T16:00:00-04:00 2019-04-01T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
the 7th LCTP Spring Symposium (April 2, 2019 8:00am) https://events.umich.edu/event/62752 62752-15460047@events.umich.edu Event Begins: Tuesday, April 2, 2019 8:00am
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

In the 7th Annual LCTP Spring Symposium, the main focus will be set on Neutrino Physics, with numerous speakers covering the field.

Event program can be found in the Symposium Program link below.

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Workshop / Seminar Mon, 26 Aug 2019 10:49:31 -0400 2019-04-02T08:00:00-04:00 2019-04-02T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Workshop / Seminar West Hall
CM-AMO Seminar | Probing Quantum Statistics and Spatial Correlations in Ultracold Gases with Rydberg Molecules (April 2, 2019 4:00pm) https://events.umich.edu/event/62328 62328-15348670@events.umich.edu Event Begins: Tuesday, April 2, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Ultralong-range Rydberg molecules (ULRRMs) provide a sensitive and versatile, in situ probe of quantum statistics and spatial correlations in quantum gases. In ULRRMs, one or more ground-state atoms are bound to an atom in a highly excited Rydberg state through atom-electron scattering. Background atoms experience a potential that is given by the shape of the Rydberg-electron probability distribution, and the photo-excitation rate is proportional to the probability of finding atoms in the original ultracold gas with appropriate atomic configurations. In the low-density, few-body regime, ULRRMs can be created with well-defined internuclear spacing, set by the radius of the outer lobe of the Rydberg electron wavefunction. For the most-deeply bound dimer molecular state in particular, the excitation rate is proportional to the pair-correlation function, g^2(R), of the initial sample, and R can be scanned by varying the principal quantum number of the target Rydberg state. We demonstrate this with ultracold, non-degenerate strontium gases and pair-separation length scales from R=1000-3000$ a_0, which is on the order of the thermal de Broglie wavelength for temperatures around 1 mu_K. Quantum statistics results in bunching for a single-component Bose gas of ^{84}Sr and Pauli exclusion for a polarized Fermi gas of ^{87}Sr. In the many-body regime the Rydberg atom is dressed by many background atoms, and for fermions the shape of the excitation spectrum can be explained in terms of Pauli blocking in the filled molecular orbitals of the final state. ULRRM excitation can be nearly non-destructive, and the time scale for molecule formation (~1 mu s) is also much faster than the inverse chemical potential or Fermi energy in quantum gases, potentially making this a valuable new probe of spatial correlations in many-body systems.

Research supported by the AFOSR (FA9550-14-1-0007), and the Robert A, Welch Foundation (C-1844)

Collaborators

F. B. Dunning, R. Ding, S. K. Kanungo, J. D. Whalen, H. Y. Rathore, S. Yoshida, J. Burgdorfer, John Sous, H. R. Sadeghpour, E. Demler, M. Wagner, and Richard Schmidt

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Workshop / Seminar Tue, 02 Apr 2019 18:16:04 -0400 2019-04-02T16:00:00-04:00 2019-04-02T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
the 7th LCTP Spring Symposium (April 3, 2019 8:00am) https://events.umich.edu/event/62752 62752-15460048@events.umich.edu Event Begins: Wednesday, April 3, 2019 8:00am
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

In the 7th Annual LCTP Spring Symposium, the main focus will be set on Neutrino Physics, with numerous speakers covering the field.

Event program can be found in the Symposium Program link below.

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Workshop / Seminar Mon, 26 Aug 2019 10:49:31 -0400 2019-04-03T08:00:00-04:00 2019-04-03T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Workshop / Seminar West Hall
Department Colloquium | The Precision Frontier of Particle Physics (April 3, 2019 4:00pm) https://events.umich.edu/event/62510 62510-15375203@events.umich.edu Event Begins: Wednesday, April 3, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

High precision technology offers a powerful new approach for particle physics. Discovering the answers to open questions such as the hierarchy problem and the nature of dark matter may in fact require a new, high precision approach instead of conventional techniques. Examples of such new physics include the axion, a solution to the strong CP problem and strongly-motivated dark matter candidate. Technologies such as atom interferometry, nuclear magnetic resonance, and high precision magnetometry allow novel, highly sensitive experiments for direct detection of dark matter and new fundamental interactions. These approaches are similar in many respects to gravitational wave detectors. I will discuss several new detectors for dark matter and/or gravitational waves. Such precision experiments will open new avenues for probing the origin and composition of the universe.

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Workshop / Seminar Wed, 03 Apr 2019 18:16:00 -0400 2019-04-03T16:00:00-04:00 2019-04-03T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Luke Miratrix, Assistant Professor, Harvard Graduate School of Education (April 5, 2019 11:30am) https://events.umich.edu/event/60717 60717-14946092@events.umich.edu Event Begins: Friday, April 5, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

The current causal inference literature on blocking has two main branches: one on larger blocks, with multiple treatment and control units in each block and the second on matched pairs, with a single treatment and control unit in each block. For larger blocks, variance estimation is relatively straightforward. For matched pairs, however, because one cannot directly estimate variance within a block we have to use estimators that look at variation across the blocks. These alternative estimators have been evaluated under different assumptions than found in the large block literature. Because of this, these two literatures do not handle cases with blocks of varying sizes, but which contain singleton treatment or control units. This has also created some confusion regarding the benefits of blocking in general. In this talk, we reconcile the literatures by carefully examining the performance of different estimators of treatment effect and of variance under several different frameworks. We also provide variance estimators for experiments with many small blocks of different sizes and for experiments with mixtures of large and small blocks. We finally discuss in which situations blocking is or is not guaranteed to reduce the variance of our estimator.

Nicole Pashley & Luke Miratrix

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Workshop / Seminar Mon, 01 Apr 2019 12:26:15 -0400 2019-04-05T11:30:00-04:00 2019-04-05T12:30:00-04:00 West Hall Department of Statistics Workshop / Seminar Luke Miratrix
Intertwined orders and fermions in holography (April 5, 2019 3:00pm) https://events.umich.edu/event/62643 62643-15416705@events.umich.edu Event Begins: Friday, April 5, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

Behind the unconventional behavior of many strongly interacting quantum systems is an intrinsically complex phase diagram exhibiting a variety of orders. These may not only compete but also cooperate with each other, describing phases with a common origin that are intertwined. Holographic techniques provide a theoretical laboratory to probe such strongly correlated systems, offering a new window into their dynamics.
In this talk I will discuss a holographic model of a striped superconductor, which provides a concrete realization of intertwined orders. I will also examine the formation and structure of Fermi surfaces in various holographic systems with broken translational invariance. In particular, we will see that sufficiently strong lattice effects generically cause the Fermi surface to dissolve, leaving behind disconnected segments. This segmentation process is reminiscent of the puzzling Fermi arc phenomenon observed in the high temperature superconductors.

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Lecture / Discussion Wed, 27 Mar 2019 13:38:25 -0400 2019-04-05T15:00:00-04:00 2019-04-05T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
Making Connections: Data Science Approaches to Understanding Mood and Cognition in the Modern Era (April 5, 2019 4:00pm) https://events.umich.edu/event/62825 62825-15477378@events.umich.edu Event Begins: Friday, April 5, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: In this talk Dr. Leow will share her reflections, as both a computational researcher and a practicing psychiatrist, on the current landscape of psychiatric neuroimaging research and where we go from here.

To this end, she argues that recent advances in data science and information technology will revolutionize the way we conceptualize psychiatric disorders and enable us to objectively quantify their symptomatology, which traditionally has been primarily based on self reports.

To illustrate, she will highlight two lines of ongoing research that apply data science approaches to the assessment of mood and cognition. In the first example, she will propose how EEG connectomics coupled with manifold learning and dimensionality reduction may allow us to measure the ‘speed of thinking’ on a sub-second time scale. In the second example, she will introduce her recent joint work with Dr. Melvin McInnis that seeks to unobtrusively turn smartphones into ‘stethoscopes’ of the brain, in real time and in the wild.



Bio: Dr. Alex Leow is an Associate Professor in the Departments of Psychiatry, Bioengineering, and Computer Science at the University of Illinois at Chicago (UIC) and an attending physician at the University of Illinois Hospital. With Dr. Olu Ajilore, Alex founded the Collaborative Neuroimaging Environment for Connectomics (CoNECt) at UIC. CoNECt is an inter-departmental research team devoted to the study of the human brain using multidisciplinary approaches of brain imaging, non-invasive brain stimulation, Big Data analytics, virtual-reality immersive visualization, and more recently mobile technologies.

Most relevant to this talk, Alex is honored to the project lead of the BiAffect project. BiAffect is the first scientific study that seeks to turn smartphones into “brain fitness trackers”, by unobtrusively inferring neuropsychological functioning using entirely passively-collected typing kinematics metadata (i.e., not what you type but how you type it) from a smartphone’s virtual keyboard. The iOS BiAffect study app now powers the first-ever crowd-sourced research study to unobtrusively measure mood and cognition in real-time using iPhones and Apple’s ResearchKit framework.

The CoNECt team’s research has been extensively featured in the news, including more recently in Chicago Tribune, Chicago Tonight, Forbes, the Wall Street Journal, the Associated Press news, and the Rolling Stone.

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Workshop / Seminar Wed, 03 Apr 2019 12:59:17 -0400 2019-04-05T16:00:00-04:00 2019-04-05T17:00:00-04:00 West Hall Michigan Institute for Data Science Workshop / Seminar Alex Leow, MD, PhD
CSEAS Graduate Student Conference. (Re)Making Memory in Southeast Asia (April 6, 2019 9:00am) https://events.umich.edu/event/61041 61041-15024927@events.umich.edu Event Begins: Saturday, April 6, 2019 9:00am
Location: West Hall
Organized By: Center for Southeast Asian Studies

Re)Making Memory in Southeast Asia is a graduate student conference and exhibition highlighting new interdisciplinary research and artistic projects focusing on issues of memory and forgetting in Southeast Asia. The one-day event culminates with a presentation by keynote speaker, Professor Eric Tagliacozzo, Cornell University, Department of History.

8:00 - 9:00 Breakfast and registration

9:00 - 9:15 Opening remarks, UM CSEAS Director Christi-Anne Castro

9:15 - 10:30 Panel 1: Constructing Identity

“Post-conflict Construction of Memory Through Mainstream Media: The Case of the Tak Bai Incident”
Ornwara Tritrakarn, Cornell University, Department of Asian Studies,

“Old stories, new heroes: Memories of masculinity in Ambon” Michael Kirkpatrick Miller, Cornell University, Department of History,

“The Royal Gift of Thai: What the Wild Boar Incident Teaches Us”
Tyler Esch, University of Hawai’i Mānoa, Department of Southeast Asian Studies,

Moniek van Rheenen, Department of Anthropology, University of Michigan, Discussant

10:30 - 11:45 Panel 2: Counter Narratives and Modes of Silence

“From "Asia as Method" to "Tây Sơn as Method"? Postwar historiography and the rise of counter-memories from the margins in the Vietnamese diaspora” Vinh Nguyen, Department of East Asian Languages and Civilizations, Harvard University

“Gender Identity and Marginalization of Vietnamese Women's Roles: The case study of HátChèo, a folk theatre in the eighteenth and nineteenth centuries” Huong Nguyen, Department of World Languages, Literature, and Culture,
Arkansas University

“Glimmers of "Pen Gan Eng": State-Sponsored Craft Fairs in Bangkok and the Aesthetics of Precarity among Silk Vendors from Surin, Thailand”
Alexandra Dalferro, Department of Anthropology, Cornell University Chao Ren, Department of History, University of Michigan, Discussant

11:45-12:45 Lunch

12:45 - 1:00 Film Screening: “Big Durian Big Apple” Azalia P. Muchransyah, SUNY Buffalo

1:15 - 2:15 Panel 3: Embodied Memory

“Temporal Emplacements Among Migrant Domestic Workers in Hong Kong”
Lai Wo, Department of Anthropology, University of Michigan

“What does it mean to remember? Cultural Memory and the Embodiment of
the Ati in the Sadsad Phenomenon”
Jemuel Jr. B. Garcia, Department of Critical Dance Studies, University of California, Riverside

Cheryl Yin, Department of Anthropology, University of Michigan, Discussant
2:30 - 3:30 Artist Talks: Photovoice Exhibition and Performance “Nostalgia, for 30-note hand crank music box.”
Can Bilir, Department of Music, Cornell University

“If age is only a number, then gender is only a word.” Understanding the circumstances of youth navigating non-traditional sexuality and gender expression in rural areas of Northern Thailand.
Colleen Towler, School of Social Work, University of Michigan

3:30 - 5:00 Keynote: Eric Tagliacozzo, Department of History, Cornell University


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If you are a person with a disability who requires an accommodation to attend this event, please reach out to us at least 2 weeks in advance of this event. Please be aware that advance notice is necessary as some accommodations may require more time for the university to arrange. Contact: alibyrne@umich.edu

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Conference / Symposium Mon, 25 Mar 2019 16:27:28 -0400 2019-04-06T09:00:00-04:00 2019-04-06T17:00:00-04:00 West Hall Center for Southeast Asian Studies Conference / Symposium conference_image
Quantitative Biology Seminar | Dynamics of intermittent neural synchronization: observations, mechanisms, and functions (April 8, 2019 12:00pm) https://events.umich.edu/event/59064 59064-14677939@events.umich.edu Event Begins: Monday, April 8, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Synchronization of neural activity in the brain is involved in a variety of brain functions including perception, cognition, memory, and motor behavior. Excessively strong, weak, or otherwise improperly organized patterns of synchronous oscillatory activity may contribute to the generation of symptoms of different neurological and psychiatric diseases. However, neuronal synchrony is frequently not perfect, but rather exhibits intermittent dynamics. The same synchrony strength may be achieved with markedly different temporal patterns of activity. I will discuss methods to describe these phenomena and will present the application of this analysis to the neurophysiological data in healthy brain, Parkinson’s disease, and drug addiction disorders. I will finally discuss potential cellular mechanisms and functional advantages of some of the observed temporal patterning of neural synchrony.

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Workshop / Seminar Mon, 08 Apr 2019 18:15:44 -0400 2019-04-08T12:00:00-04:00 2019-04-08T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | Jet substructure at RHIC and the LHC (April 8, 2019 4:00pm) https://events.umich.edu/event/62608 62608-15410179@events.umich.edu Event Begins: Monday, April 8, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

In high energy proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), high energy sprays of particles, called jets, are one of the most copiously produced final states. Jets form when a quark or gluon is produced in a scattering process, and because of confinement, these quarks and gluons nonperturbatively form a collimated spray of hadrons. While jets are one of the most frequently used objects in physics analyses at RHIC and the LHC, it was only recently realized that the structure of jets can probe a wide variety of physics at collider facilities. In this talk I will discuss the breadth of physics that can be probed by studying the constituents of jets, with a focus on recent results from the LHCb experiment.

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Workshop / Seminar Mon, 08 Apr 2019 18:15:44 -0400 2019-04-08T16:00:00-04:00 2019-04-08T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Honors 222: Are We Alone? (April 9, 2019 2:30pm) https://events.umich.edu/event/62909 62909-15492427@events.umich.edu Event Begins: Tuesday, April 9, 2019 2:30pm
Location: West Hall
Organized By: LSA Honors Program

Student Poster Exhibition
Where: 337/340 West Hall
When: 2:30-3:50pm
Tuesday, April 9 and Thursday April 11
Talk with students about their research!
Light refreshments served.

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Presentation Fri, 05 Apr 2019 13:51:32 -0400 2019-04-09T14:30:00-04:00 2019-04-09T15:50:00-04:00 West Hall LSA Honors Program Presentation Students Showing Interstellar Communication Poster
Helmut W. Baer Lecture | The Neutron Lifetime Puzzle (April 10, 2019 4:00pm) https://events.umich.edu/event/60984 60984-15000011@events.umich.edu Event Begins: Wednesday, April 10, 2019 4:00pm
Location: West Hall
Organized By: Department Colloquia

Neutrons make up half of all matter but become unstable when freed from the nucleus. The precise value of the neutron lifetime plays an important role in nuclear and particle physics and cosmology. Professor Liu will describe the latest measurement, which traps neutrons by levitating neutrons with a large array of permanent magnets. The lifetime measured this way appears different than that measured with a beam of neutrons leading some to conjecture their disappearance into an undetectable state.

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Lecture / Discussion Thu, 07 Mar 2019 13:43:05 -0500 2019-04-10T16:00:00-04:00 2019-04-10T17:00:00-04:00 West Hall Department Colloquia Lecture / Discussion Chen-Yu Liu
Exploring the Computational Universe: Discoveries and Implications (April 11, 2019 11:30am) https://events.umich.edu/event/62332 62332-15353055@events.umich.edu Event Begins: Thursday, April 11, 2019 11:30am
Location: West Hall
Organized By: The Center for the Study of Complex Systems

Abstract: This talk will discuss my current views about the basic science and the practical applications of phenomena in the computational universe of simple programs. I'll talk about my current ideas about modeling, abstraction, and mining the computational universe for technology. I'll also talk about implications for AI, SETI, and basic questions about the role of humans in the computational universe.

About: Stephen Wolfram is the creator of Mathematica, Wolfram|Alpha and the Wolfram Language; the author of A New Kind of Science; and the founder and CEO of Wolfram Research. In recognition of his early work in physics and computing, Wolfram became in 1981 the youngest recipient of a MacArthur Fellowship. Following his scientific work on complex systems research, in 1986 Wolfram founded the first journal in the field: Complex Systems.

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Workshop / Seminar Wed, 10 Apr 2019 09:59:25 -0400 2019-04-11T11:30:00-04:00 2019-04-11T13:00:00-04:00 West Hall The Center for the Study of Complex Systems Workshop / Seminar Stephen Wolfram
Honors 222: Are We Alone? (April 11, 2019 2:30pm) https://events.umich.edu/event/62909 62909-15492428@events.umich.edu Event Begins: Thursday, April 11, 2019 2:30pm
Location: West Hall
Organized By: LSA Honors Program

Student Poster Exhibition
Where: 337/340 West Hall
When: 2:30-3:50pm
Tuesday, April 9 and Thursday April 11
Talk with students about their research!
Light refreshments served.

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Presentation Fri, 05 Apr 2019 13:51:32 -0400 2019-04-11T14:30:00-04:00 2019-04-11T15:50:00-04:00 West Hall LSA Honors Program Presentation Students Showing Interstellar Communication Poster
Statistics Department Seminar Series: Jeff Douglas, Professor, Department of Statistics, University of Illinois at Urbana-Champaign (April 12, 2019 11:30am) https://events.umich.edu/event/60718 60718-14946093@events.umich.edu Event Begins: Friday, April 12, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

Latent class models for learning in online and e-learning settings are introduced. A real data example of an intervention for learning rotational skills in spatial reasoning is used to illustrate restricted latent class models for item responses, known as cognitive diagnosis models, that are coupled with transition models for learning. An array of possibilities are considered that include models with explanatory variables, such as intervention and practice effects, as well as more parsimonious first-order Markov models. In addition, we consider a higher-order continuous variable that may be thought of as general learning ability. The value of response times in assessing learning is considered, and the concept of fluency in which learned attributes are applied more and more easily is introduced. Extensions of the models that include parameters for the instructional value of individual items are given, and MCMC methods for fitting the models are discussed along with results from numerical studies. An R package that includes the spatial reasoning dataset and tools for fitting learning models is reviewed and future directions and new possibilities for applying learning models in e-learning environments are discussed.

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Workshop / Seminar Mon, 01 Apr 2019 12:28:37 -0400 2019-04-12T11:30:00-04:00 2019-04-12T12:30:00-04:00 West Hall Department of Statistics Workshop / Seminar Jeff Douglas
Cosmology and Astrophysics of the Twin Higgs (April 12, 2019 3:00pm) https://events.umich.edu/event/62644 62644-15416707@events.umich.edu Event Begins: Friday, April 12, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

The Twin Higgs model is an attractive solution to the little Hierarchy problem with top partners that are neutral under SM gauge charges. The framework is consistent with the null result of LHC colored top partner searches while offering many alternative discovery channels. Depending on model details, the phenomenology looks very different: either spectacular long-lived particle signals at colliders, or a plethora of unusual cosmological and astrophysical signatures via the existence of a predictive hidden sector. I will examine the latter possibility, and describe how the asymmetrically reheated Mirror Twin Higgs provides a predictive framework for a highly motivated and highly non-trivial interacting dark sector, with correlated signals in the CMB, Large Scale Structure, and direct detection searches, as well as higgs precision measurements at colliders. This provides a vivid example of the collider-cosmology complementarity, and motivates a variety of new astrophysical searches, including the search for X-ray point sources from Mirror Stars, that are motivated by the hierarchy problem.

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Lecture / Discussion Wed, 27 Mar 2019 13:39:58 -0400 2019-04-12T15:00:00-04:00 2019-04-12T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
HET Seminars | Cosmology and Astrophysics of the Twin Higgs (April 12, 2019 3:00pm) https://events.umich.edu/event/62929 62929-15517953@events.umich.edu Event Begins: Friday, April 12, 2019 3:00pm
Location: West Hall
Organized By: HET Seminars

The Twin Higgs model is an attractive solution to the little Hierarchy problem with top partners that are neutral under SM gauge charges. The framework is consistent with the null result of LHC colored top partner searches while offering many alternative discovery channels. Depending on model details, the phenomenology looks very different: either spectacular long-lived particle signals at colliders, or a plethora of unusual cosmological and astrophysical signatures via the existence of a predictive hidden sector. I will examine the latter possibility, and describe how the asymmetrically reheated Mirror Twin Higgs provides a predictive framework for a highly motivated and highly non-trivial interacting dark sector, with correlated signals in the CMB, Large Scale Structure, and direct detection searches, as well as higgs precision measurements at colliders. This provides a vivid example of the collider-cosmology complementarity, and motivates a variety of new astrophysical searches, including the search for X-ray point sources from Mirror Stars, that are motivated by the hierarchy problem.

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Workshop / Seminar Mon, 08 Apr 2019 09:39:58 -0400 2019-04-12T15:00:00-04:00 2019-04-12T16:00:00-04:00 West Hall HET Seminars Workshop / Seminar West Hall
Data Science at the New York Times (April 15, 2019 4:00pm) https://events.umich.edu/event/62827 62827-15477379@events.umich.edu Event Begins: Monday, April 15, 2019 4:00pm
Location: West Hall
Organized By: Michigan Institute for Data Science

Abstract: The Data Science group at The New York Times develops and deploys machine learning solutions to newsroom and business problems. Re-framing real-world questions as machine learning tasks requires not only adapting and extending models and algorithms to new or special cases but also sufficient breadth to know the right method for the right challenge. I’ll first outline how unsupervised, supervised, and reinforcement learning methods are increasingly used in human applications for description, prediction, and prescription, respectively. I’ll then focus on the ‘prescriptive’ cases, showing how methods from the reinforcement learning and causal inference literatures can be of direct impact in engineering, business, and decision-making more generally.

Bio: At Columbia, Chris is a founding member of the executive committee of the Data Science Institute, the Department of Systems Biology, and is affiliated faculty in Statistics. He is a co-founder and co-organizer of hackNY (http://hackNY.org), a nonprofit which since 2010 has organized once a semester student hackathons and the hackNY Fellows Program, a structured summer internship at NYC startups. Prior to joining the faculty at Columbia he was a Courant Instructor at NYU (1998-2001) and earned his PhD at Princeton University (1993-1998) in theoretical physics. He is a Fellow of the American Physical Society and is a recipient of Columbia’s Avanessians Diversity Award.

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Workshop / Seminar Wed, 03 Apr 2019 13:04:51 -0400 2019-04-15T16:00:00-04:00 2019-04-15T17:00:00-04:00 West Hall Michigan Institute for Data Science Workshop / Seminar Chris Wiggins, PhD
HEP-Astro Seminar | Significant Excess of Electron-Like Events from the MiniBooNE Short-Baseline Neutrino Experiment (April 15, 2019 4:00pm) https://events.umich.edu/event/62110 62110-15293421@events.umich.edu Event Begins: Monday, April 15, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The MiniBooNE short-baseline neutrino experiment at Fermilab observes a significant excess of electron-like events. From 2.4E21 protons on target in neutrino and antineutrino mode, a total electron-neutrino charged-current quasi-elastic excess of 460.5 +- 99.0 events (4.7 sigma) is observed in the neutrino energy range from 200-1250 MeV. If interpreted in a standard two-neutrino oscillation model, the best oscillation fit to the excess has a probability of 21.1%, while the background-only fit has a chisquare probability of 6E-7 relative to the best fit. The MiniBooNE data are consistent in energy and magnitude with the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), and the significance of the combined LSND and MiniBooNE excesses is 6 sigma. All of the major backgrounds are constrained by in-situ event measurements, so non-oscillation explanations would need to invoke new anomalous background processes.

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Workshop / Seminar Mon, 15 Apr 2019 18:15:34 -0400 2019-04-15T16:00:00-04:00 2019-04-15T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Optics of Dirac and Weyl fermions in topological materials (April 16, 2019 4:00pm) https://events.umich.edu/event/62977 62977-15528488@events.umich.edu Event Begins: Tuesday, April 16, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Relativistic Dirac and Weyl fermions were extensively studied in quantum field theory. Recently they emerged in the nonrelativistic condensed-matter setting as gapless quasiparticle states in some types of crystals. Notable examples of 2D systems include graphene and surface states in topological insulators such as Bi_2Se_3. Their 3D implementation is Dirac and Weyl semimetals. Most of the research has been focused on their topological properties and electron transport. However, their optical properties are no less exciting. Optical phenomena provide valuable insight into the fascinating physics of these materials. Optical spectroscopy can provide a cleaner and more straightforward way of studying topological properties of electron states as compared to transport measurements. Moreover, unusual optical properties of these materials can be utilized in future optoelectronic devices. I will discuss several examples illustrating these points. They include bulk and surface polaritons in Weyl semimetals, magnetooptics of Dirac and Weyl semimetals, and the nonlocal nonlinear optical response of graphene and topological insulators.

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Workshop / Seminar Tue, 16 Apr 2019 18:15:42 -0400 2019-04-16T16:00:00-04:00 2019-04-16T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Applied Physics Seminar: Spike patterns of neuronal populations in the hippocampus during wake and sleep (April 17, 2019 12:00pm) https://events.umich.edu/event/61442 61442-15106028@events.umich.edu Event Begins: Wednesday, April 17, 2019 12:00pm
Location: West Hall
Organized By: Applied Physics

My lab is interested in the role that neuronal firing patterns play in the encoding, storage, transfer and retrieval of information by the brain. To study this question, we focus on in-vivo extracellular recordings and computational analyses of spike trains from up to 100 neurons from the hippocampus and cortex during activity and sleep, combined with optogenetic and chemogenetic manipulations. In this talk, I will discuss the distinct patterns that we see in these spike trains on multiple timescales and how they change during and across different brain network states. Because these activities are found in the hippocampus, I will discuss their relationship to memory. Finally, I will describe current efforts to evaluate the temporal structure in neuronal spike trains using unsupervised machine learning by hidden Markov models.

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Lecture / Discussion Wed, 10 Apr 2019 16:13:14 -0400 2019-04-17T12:00:00-04:00 2019-04-17T13:00:00-04:00 West Hall Applied Physics Lecture / Discussion West Hall
Department Colloquium | Memory, directed aging and Nature's greed (April 17, 2019 4:00pm) https://events.umich.edu/event/62914 62914-15494565@events.umich.edu Event Begins: Wednesday, April 17, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

In a crystal with only one atom per unit cell, all atoms play the same role in producing the solid's global response to external perturbations. Disordered materials are not similarly constrained and a new principle emerges: independence of bond-level response. This allows one to drive the system to different regimes of behavior by successively removing individual bonds. We can thus exploit disorder to achieve unique, varied, textured and tunable global response or long-range interactions inspired by allosteric behavior in proteins. While this approach is successful for systems with only a few degrees of freedom, it is difficult to scale up the number of elements to be controlled or scale down the size of the individual components. However, because a material has a memory of under what conditions it has been aged, we can direct the aging using Nature's greedy algorithms to achieve a variety of mechanical functionalities.

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Workshop / Seminar Wed, 17 Apr 2019 18:15:41 -0400 2019-04-17T16:00:00-04:00 2019-04-17T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Quantitative Biology Seminar | Lineage tracing in cellular reprogramming reveals selective dynamics (April 19, 2019 11:00am) https://events.umich.edu/event/63147 63147-15578798@events.umich.edu Event Begins: Friday, April 19, 2019 11:00am
Location: West Hall
Organized By: Department of Physics

Cellular reprogramming is a phenomenon where mature, specialized cells can be reprogrammed to immature cells capable of developing into all tissues of the body. Do cells individual cells differ in their ability to reprogram? We address this using cellular barcoding based lineage tracing, and demonstrate that reprogramming dynamics in large "interacting" populations are dominated by “elite” clones [1]. This work highlights the importance of cellular interactions and/or epigenetic heterogeneity in fate programming outcomes. In contrast, tissue regeneration in animals exhibit neutral dynamics between the underlying population of stem cells [2]. Taken together, we show that looking at cell fate transition from the lens of eco-evolutionary lens shed light on underlying biology.

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Workshop / Seminar Fri, 19 Apr 2019 18:15:32 -0400 2019-04-19T11:00:00-04:00 2019-04-19T12:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Michael Sobel, Professor, Department of Statistics, Columbia University (April 19, 2019 11:30am) https://events.umich.edu/event/60719 60719-14946094@events.umich.edu Event Begins: Friday, April 19, 2019 11:30am
Location: West Hall
Organized By: Department of Statistics

Neuroscientists often use functional magnetic resonance imag- ing (fMRI) to infer effects of treatments on neural activity in brain regions. In a typical fMRI experiment, each subject is observed at several hundred time points. At each point, the blood oxygenation level dependent (BOLD) response is measured at 100,000 or more locations (voxels). Typically, these responses are modeled treating each voxel separately, and no rationale for interpreting associations as effects is given. Building on Sobel and Lindquist (2014), who used potential outcomes to define unit and average effects at each voxel and time point, we define and estimate both “point” and “cumu- lated” effects for brain regions. Second, we construct a multi-subject multi-voxel multi-run whole brain causal model with explicit param- eters for regions. We justify estimation using BOLD responses av- eraged over voxels within regions, making feasible estimation for all regions simultaneously, and facilitating inference about association between effects in different regions. We apply the model to a study of pain, finding effects in standard pain regions; we also observe more cerebellar activity than observed in previous studies using prevailing methods. We visualize results using whole-brain maps of effects and spatio-temporal correlation plots that illustrate temporally lagged re- lationships between brain regions.
By Michael E. Sobel†,‡, and Martin A. Lindquist†,§ Columbia University‡ and Johns Hopkins University§

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Workshop / Seminar Fri, 12 Apr 2019 15:45:50 -0400 2019-04-19T11:30:00-04:00 2019-04-19T12:30:00-04:00 West Hall Department of Statistics Workshop / Seminar Michael Sobel
HEP-Astro Seminar | Picosecond Timing: extending the physics potential of the High Luminosity LHC with the CMS MIP timing detector (April 22, 2019 4:00pm) https://events.umich.edu/event/63020 63020-15536914@events.umich.edu Event Begins: Monday, April 22, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The High Luminosity Large Hadron Collider (HL-LHC) is an upgrade to the Large Hadron Collider at CERN, which will extend the accelerator's potential for new discoveries in physics. This upgrade will increase the rate of collisions by a factor of five beyond the original design value and the total collisions created by a factor ten. To meet the challenging conditions of the HL-LHC, the Compact Muon Solenoid (CMS) detector is undergoing an extensive Phase 2 Upgrade program. In particular, a new precision timing detector with hermetic coverage up to a pseudo-rapidity of |η|=3 will measure minimum ionizing particles (MIPs) with a time resolution of 30-40 ps. This measurement of the time coordinate will reduce the effects of the high levels of pile-up expected at the HL-LHC and bring new capabilities to the CMS detector. In this seminar, I will discuss the impact on the HL-LHC physics program as well as the design and technology of this new detector.

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Workshop / Seminar Mon, 22 Apr 2019 18:15:25 -0400 2019-04-22T16:00:00-04:00 2019-04-22T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Special Life After Graduate School Seminar | Applied Physics Applied (April 23, 2019 12:00pm) https://events.umich.edu/event/63256 63256-15603734@events.umich.edu Event Begins: Tuesday, April 23, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Catalin Florea (Applied Physics PhD, 2002) will share notes on his (non-academic) early and mid-career path – from landing the first job deep into Midwest, to working now in R&D for a Fortune 100 company. Achievements and setbacks will be discussed, and an informal Q & A session will provide an opportunity to connect with the speaker.

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Workshop / Seminar Tue, 23 Apr 2019 18:15:26 -0400 2019-04-23T12:00:00-04:00 2019-04-23T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | The precision frontier: hunting for new short-range forces with AMO-based sensors (April 23, 2019 4:00pm) https://events.umich.edu/event/63282 63282-15611985@events.umich.edu Event Begins: Tuesday, April 23, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

We normally think of large accelerators and massive detectors when we consider the frontiers of elementary particle physics, pushing to understand the universe at higher and higher energy scales. However, several tabletop low-energy experiments are positioned to discover a wide range of new physics beyond the Standard model, where feeble interactions require precision measurements rather than high energies. In high vacuum, optically-levitated dielectric nanospheres achieve excellent decoupling from their environment, making force sensing at the zeptonewton level (10^{-21} N) achievable. In this talk I will describe our progress towards using these sensors for tests of the Newtonian gravitational inverse square law at micron length scales. Optically levitated dielectric objects show promise for a variety of other applications, including searches for gravitational waves. Finally, I will discuss the Axion Resonant InterAction Detection Experiment (ARIADNE), a precision magnetometry experiment using laser-polarized 3-He gas to search for a notable dark-matter candidate: the QCD axion. ​

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Workshop / Seminar Tue, 23 Apr 2019 18:15:26 -0400 2019-04-23T16:00:00-04:00 2019-04-23T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Axion Dark Matter and Neutrinoless Double-Beta Decay: New Techniques for New Physics (April 24, 2019 4:00pm) https://events.umich.edu/event/60195 60195-14849034@events.umich.edu Event Begins: Wednesday, April 24, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Two of the biggest open questions in the Standard Model of Particle Physics are: is the neutrino its own antiparticle, a Majorana particle, and is Peccei-Quinn Symmetry with the resulting axion the solution to the strong CP problem. The answer to these questions is a portal to new physics and the answer to the even bigger questions of the generation of the matter-antimatter asymmetry and the nature of dark matter. My group works to address these questions with searches for neutrinoless double-beta decay and ultra-light axions. In this talk, I will review the physics that connects these two efforts, the current status of the fields, and our R&D efforts towards the next-generation experiments.

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Workshop / Seminar Wed, 24 Apr 2019 18:15:23 -0400 2019-04-24T16:00:00-04:00 2019-04-24T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Dissertation Defense: Design and Analysis of Sequential Randomized Trials with Applications to Mental Health and Online Education (April 25, 2019 12:00pm) https://events.umich.edu/event/63227 63227-15595499@events.umich.edu Event Begins: Thursday, April 25, 2019 12:00pm
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

Dynamic treatment regimes, also called adaptive interventions, guide sequential treatment decision-making in a variety of fields, including healthcare and education. Dynamic treatment regimes accommodate differences between individuals and changes in individuals over time. Sequential randomized trials are a specific type of trial design useful for developing high-quality dynamic treatment regimes. Sequential randomized trials utilize re-randomization of individuals over time in order to discover how to sequence, time, and personalize treatments. Two of the most commonly used sequential randomized trial designs are sequential multiple assignment randomized trials and micro-randomized trials.

In this thesis, we contribute to both the design and analysis of sequential randomized trials. We describe design considerations for sequential randomized trials in online education. We present the design and analysis for a sequential randomized trial developed to reduce dropout in a massively open online course. We also develop statistical methodology and sample size formulae for sequential multiple assignment randomized trial designs which include cluster-level randomization. The techniques are inspired by a trial aiming to develop high-quality dynamic treatment regimes for mental health clinics. Lastly, we illustrate the design, describe the analysis, and present results of a large micro-randomized trial aiming to develop mobile health interventions for improving medical interns' mental health.

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Other Tue, 16 Jul 2019 14:25:45 -0400 2019-04-25T12:00:00-04:00 2019-04-25T14:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Dissertation Defense: Scalable classification methods with applications to healthcare claims and automotive dealership data (April 25, 2019 3:00pm) https://events.umich.edu/event/63305 63305-15634623@events.umich.edu Event Begins: Thursday, April 25, 2019 3:00pm
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

With technology advances in recent years, sensing and media storage capabilities have enabled the generation of enormous amounts of information, often in the form of large data sets in different scientific fields such as biology, marketing and medicine. As this vast amount of data has opened a wealth of opportunities for data analysis, computationally scalable methods become increasingly important for statistical modeling. This thesis focuses on developing scalable classification methods and their applications to automotive dealerships and healthcare problems.

The first project studies parameter estimation of customers' and dealerships' consumption preference for the automotive market, which determines the manufacturers' profits. Most existing methods assume that the dealerships are rational and hence aim to maximize profits, which conflicts with observations. We propose a structural Bayesian model for customers’ and dealerships’ preference which aims to maximize a flexible utility function. Further we develop an MCMC algorithm utilizing parallel computing to estimate model parameters. The model is calibrated to data from a manufacturer, and the estimates are used in a simulation model to design optimal financial incentive offers to maximize profits.

The second project focuses on the two-class classification problem based on the area under the receiver operating curve (AUC), which is often considered as a more comprehensive measure for the performance of a classifier comparing with the misclassification error. Maximizing the empirical AUC directly, however, is computationally challenging as naive computation of the AUC requires quadratic time complexity, while computing the misclassification error only requires linear time complexity. Further, the optimization involves indicator functions and it is NP-hard. In this project, we propose a non-convex differentiable surrogate function for the AUC, and further develop a scalable algorithm to optimize this surrogate loss function. The proposed algorithm takes advantage of the selection tree data structure and also uses a truncated Newton strategy so that the computational complexity of the optimization scales at the quasilinear time. In the setting of linear classification, we also show that the estimated coefficients enjoy theoretical asymptotic consistency. Finally, we evaluate the performance of the proposed method using both simulation studies and two data sets, one for normal/abnormal vertebral column classification and the other for behaving/not-behaving network visit classification, and show that the proposed method outperforms the support vector machine (SVM) in terms of the AUC.

The last project is motivated by the problem of predicting midterm mortality of patients using the Ninth Revision, International Classification of Diseases (ICD-9) codes, which is relevant for healthcare and clinical research. The ICD-9 contains a list of standard six-character alphanumeric codes recording useful clinical information including patient diagnoses and procedures. However, the number of ICD-9 codes in a specific study is often large, on the order of thousands or tens of thousands, and the dependence structure among ICD-9 codes is complicated, which pose statistical challenges for using the ICD-9 codes. To address these challenges, we develop a supervised embedding method that combines an unsupervised criterion for learning latent representations of ICD-9 codes and a Deep Set neural network model for classification, which is invariant with respect to the ordering of the ICD-9 codes. The proposed supervised embedding method has the advantage of modeling the inter-relationship within ICD-9 codes and the nonlinear relationship between codes and the outcome variable simultaneously, and it can also be naturally extended to the semi-supervised learning setting. The model is trained using the stochastic gradient descent (SGD) approach, which allows the entire database to be stored on multiple computing nodes and hence makes the method suitable for analyzing large data sets. We have applied the proposed method to 1-year mortality prediction using the Medical Information Mart for Incentive Care III (MIMIC-III) database and achieved superior performance in comparison with several benchmark models.

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Other Tue, 16 Jul 2019 14:25:06 -0400 2019-04-25T15:00:00-04:00 2019-04-25T17:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
CM Theory Seminar | Towards exciton optomechanics in suspended 2D semiconductors (April 25, 2019 4:00pm) https://events.umich.edu/event/62425 62425-15364107@events.umich.edu Event Begins: Thursday, April 25, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Excitons, made of electron-hole pairs bound by Coulomb interaction, provide compelling opportunities for applications in optoelectronics, information storage, non-volatile logic. However, the small binding energy of exciton in conventional semiconductors jeopardizes its integration and potentials in modern optoelectronics schemes. In the past decade, a new type of two-dimensional semiconductors, mainly transition metal dichalcogenides (TMDs), attract tremendous interests with much larger exciton binding energy. Thus, stable excitonic effects up to room temperature can give rise to extremely strong light-matter interaction. Together with their ultra-lightweight and other emerging properties, such strong excitonic interaction in 2D TMD opens up the possibility to optically control properties of monolayer semiconductors over the suspended structure.

In this talk, I will first review this new type of 2D semiconductors and interesting device physics by employing the structure of nanoelectromechanical systems (NEMS). Then I’ll present our study of exciton-induced nonlinearities in suspended TMD monolayers, where we achieved a robust optical bistability near the exciton resonance. Our results also demonstrate a helicity-dependent optical switching that enables control of light not only by light intensity but also by its polarization using monolayer materials. Additionally, I will discuss our recent results on dynamically manipulating the mechanical motion of a suspended 2D semiconductor through its exciton resonance, without an optical cavity structure.

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Workshop / Seminar Thu, 25 Apr 2019 18:15:24 -0400 2019-04-25T16:00:00-04:00 2019-04-25T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Dissertation Defense: Statistical Learning for Networks with Node Features (April 26, 2019 1:00pm) https://events.umich.edu/event/63262 63262-15603740@events.umich.edu Event Begins: Friday, April 26, 2019 1:00pm
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

Network data represent connectivity relationships between individuals of interest and are common in many scientific fields, including biology, sociology, medicine and healthcare. Often, additional node features are also available together with the data on relationships. Both types of data contain important information about individual characteristics and the population structure. This thesis focuses on developing statistical machine learning methods and theory for network data with node features.

We first study the problem of community detection for networks with node features using a model-based approach. Most existing models make strong conditional independence assumptions between the network, features and community memberships, which limits the applicability of the model. In our work, we develop a general statistical framework to describe the dependence structure between the link structure, node features and communities. Further, we propose two families of models that are the most general under this framework with the least conditional independence assumptions between the three components. We have established mild conditions for model identifiability and developed variational EM algorithms to estimate model parameters and community memberships. Extensive simulation studies and application to a food web and a lawyer friendship network indicate that the proposed methods work well.

The second project focuses on the problem of node classification using both individual features and the network. In a classical setting, data points are assumed independent and identically distributed, and a data point is classified using only its own features. When a network between the data points is available, it often contains additional information about class memberships and can be utilized to improve classification performance. In this work, we develop a general statistical framework for network augmented classification. Under this framework, we derive the optimal Bayes classifiers for two general families of distributions incorporating node features and networks. Further, we establish asymptotic consistency results for plug-in classifiers with respect to the optimal ones under the two families. We have also applied these general approaches to specific models and developed effective classifiers for practical use. The proposed methods have been evaluated using both simulation studies and a teenage friendship network, and show promising results.

The final contribution of this thesis is on link prediction for incomplete network data. Most existing link prediction methods require at least partial observation of connections for every node. In real-world networks, however, there often exist nodes that do not have any link information, and it is of interest to make link predictions for them using only their node features. We consider a general setup in which a network consists of three types of nodes, nodes only having feature information, nodes only having link information, and nodes having both. Our goal is to make link predictions for nodes having only feature information. Under this setting, we have proposed a family of generative models for incomplete networks with node features, and we have developed a variational auto-encoder algorithm for model estimation and link prediction and investigated different encoder structures. We have also designed a cross-validation scheme under the problem setting for model selection. The proposed method has been evaluated on an online social network and two citation networks and achieves superior performance comparing with existing methods.

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Other Tue, 16 Jul 2019 14:25:25 -0400 2019-04-26T13:00:00-04:00 2019-04-26T15:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Informal HEP-Astro Seminar | Paleo Detectors - Digging for Dark Matter (April 29, 2019 4:00pm) https://events.umich.edu/event/63406 63406-15671658@events.umich.edu Event Begins: Monday, April 29, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Direct detection experiments have delivered impressive limits on the interaction strength of dark matter with nuclei. A large experimental program is underway to extend the sensitivity of direct detection experiments, however, such experiments are becoming increasingly difficult and costly. Recently, we proposed paleo-detectors as analternative approach to the direct detection of dark matter: Instead of searching for dark matter induced nuclear recoils in a real-time laboratory experiment, we propose to search for the traces of dark matter interactions recorded in ancient minerals over geological time-scales. In this talk I will discuss this proposal, including ways to mitigate backgrounds and methods to read out tracks from ancient minerals. I will also briefly discuss some preliminary results for applications of paleo-detectors beyond dark matter, e.g. for searching for neutrinos from core collapse supernovae.

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Workshop / Seminar Mon, 29 Apr 2019 18:15:17 -0400 2019-04-29T16:00:00-04:00 2019-04-29T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Dissertation Defense: Uniform Consistency of Spectral Embeddings (May 2, 2019 10:00am) https://events.umich.edu/event/63316 63316-15636689@events.umich.edu Event Begins: Thursday, May 2, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

Spectral methods are a staple of modern statistics. For statistical learning tasks such as clustering or classification, one can featurize the data with spectral methods and then perform the task on the features. Despite the success and wide use of spectral methods, certain theoretical properties of spectral methods are not well-understood. In this oral defense, we investigate the uniform convergence (as opposed to convergence in an ``average'' sense) of the spectral embeddings obtained from the leading eigenvectors of certain similarity matrices to their population counterparts. We will first introduce necessary preliminaries and review existing results on this topic, and then explain the motivations and benefits for studying the convergence in a uniform sense. After that, we present the two main results in our work. The first result is a general perturbation result for orthonormal bases of invariant subspaces that can serve as a general recipe for establishing uniform consistency type results. The second result in an application of the first result to normalized spectral clustering---by tapping into the rich literature of Sobolev spaces and exploiting some concentration results in Hilbert spaces, we are able to prove a finite sample error bound on the uniform consistency error of the spectral embeddings in normalized spectral clustering.

The material in this oral defense is based on the first chapter of Ruofei Zhao's thesis "Convergence and Consistency Results in Spectral Clustering and Gaussian Mixture Models".

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Other Tue, 16 Jul 2019 14:24:43 -0400 2019-05-02T10:00:00-04:00 2019-05-02T12:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Statistics Graduate Graduation Reception (May 3, 2019 2:30pm) https://events.umich.edu/event/61204 61204-15052047@events.umich.edu Event Begins: Friday, May 3, 2019 2:30pm
Location: West Hall
Organized By: Department of Statistics

The Graduation Reception for Statistics Graduate Students will be held on May 3, 2019 in 340 West Hall from 2:30pm - 4:30pm. Doors will open at 2:15pm.

More details TBA

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Reception / Open House Wed, 24 Apr 2019 08:43:32 -0400 2019-05-03T14:30:00-04:00 2019-05-03T16:30:00-04:00 West Hall Department of Statistics Reception / Open House West Hall
Dissertation Defense: Just-In-Time Adaptive Interventions: Experiment, Inference and Online Learning (May 13, 2019 1:00pm) https://events.umich.edu/event/63520 63520-15773891@events.umich.edu Event Begins: Monday, May 13, 2019 1:00pm
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

The use and development of mobile interventions are experiencing rapid growth. Ideally, mobile devices can be used to provide treatment/support whenever needed and to adapt treatment to the context of the user. Just-in-time Adaptive Interventions (JITAIs) are composed of decision rules that map a user’s context (e.g., user's behaviors, location, current time, social activity, stress and urges to smoke) to a treatment that is delivered to the user via the mobile device in near real-time. Advancements in mobile health engineering and technology (e.g., passive stress sensing) continue to bring us closer to being able to provide interventions in this way. However, a number of important gaps in data science must be addressed before mobile devices can be used to deliver on the promise of JITAIs. First, there is a need for experimental designs to collect data that can be used to assess the effectiveness of the sequence of treatments delivered by a mobile device on health outcomes in order to support the development of JITAIs. Second, there is a need for data-driven methods to inform the construction of efficacious JITAIs. In the vast majority of currently deployed JITAIs, the decision rules underpinning JITAIs are formulated using domain expertise and clinical experience, with very limited use of data evidence.

In this dissertation, we make several contributions by tackling the above mentioned data science barriers to effective JITAI development in mobile health. First, we propose a micro-randomized trial (MRT) design and develop the primary analysis for assessing the proximal causal effect of treatments. In addition, we develop stratified micro-randomized trials for the setting where there is a time-varying, discrete variable and the primary analysis focuses on how the effectiveness of interventions changes with this variable. We also develop a novel algorithm to design randomization scheme for this setting when there is an average constraint on the number of times interventions that should be sent in a certain time interval. Second, we develop a semi-parametric model to estimate the long-term average of health outcomes that would accrue should a given JITAI be followed. We derive asymptotic theory for the consistency and asymptotic normality of the proposed estimator. Third, we develop an online learning algorithm that continuously learns and improves the JITAI as the data is collected from the user. The proposed algorithm introduces a proxy of future outcomes based on a dosage variable to capture the delayed effect of sending the interventions due to the treatment burden.

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Other Tue, 16 Jul 2019 14:24:15 -0400 2019-05-13T13:00:00-04:00 2019-05-13T15:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Special HEP-Astro Seminar | Searching for Dark Matter from the Lowest to the Highest Energies (May 13, 2019 1:00pm) https://events.umich.edu/event/63481 63481-15726893@events.umich.edu Event Begins: Monday, May 13, 2019 1:00pm
Location: West Hall
Organized By: Department of Physics

Dark Matter (DM) is a long standing puzzle in fundamental physics and goal of a diverse research program. In underground experiments such as LZ we search for DM directly using lowest possible energy thresholds, at the LHC we seek to produce dark matter at the very highest energies, and using telescopes we look for telltale signatures in the cosmos. All these detection methods probe different parts of the possible parameters space with complementary strengths. I will present current DM searches, their connection and how an interdisciplinary program bridging different experimental frontiers can achieve optimal sensitivity. Finally, I will highlight recent theoretical and experimental developments and the near term discovery prospects in upcoming experiments.

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Workshop / Seminar Fri, 03 May 2019 15:06:58 -0400 2019-05-13T13:00:00-04:00 2019-05-13T14:30:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Special Data Visualization Workshop (May 14, 2019 3:00pm) https://events.umich.edu/event/63524 63524-15775923@events.umich.edu Event Begins: Tuesday, May 14, 2019 3:00pm
Location: West Hall
Organized By: Physics Workshops & Conferences

Scientific research can be a slow and laborious process. The absolute final step in the process is to then communicate your exciting scientific findings to other scientists both in and outside of your field. Yet it is sometimes at this final step where the least amount of time is spent. In this interactive 90-min workshop, I will give a basic introduction to making scientific figures using Adobe Illustrator and Blender3D. I will go over the basics of these software, how they treat objects, and the useful hotkeys for speeding up workflow. In the first hour, I will introduce Illustrator and cover topics like workflow; importing external plots/figures; creating patterns (i.e. schematic atomic lattices); and creating 3D structures. In the last half-hour I will give a brief introduction to Blender, a powerful (and free) open-source software for rendering 3D objects. I will go over the basics of how Blender treats objects/structures, lighting, and rendering a scene.

**All are welcome, but it is strongly recommended that participants bring laptops with Adobe Illustrator CC (or at least CS6) and Blender3D pre-installed so that you can follow along with the demos.**

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Workshop / Seminar Thu, 09 May 2019 15:57:54 -0400 2019-05-14T15:00:00-04:00 2019-05-14T16:30:00-04:00 West Hall Physics Workshops & Conferences Workshop / Seminar An introduction to making scientific figures with Illustrator & Blender
Dissertation Defense: Statistical Tools for Samples of Weighted Networks with Applications to Neuroimaging (May 15, 2019 10:00am) https://events.umich.edu/event/63584 63584-15806547@events.umich.edu Event Begins: Wednesday, May 15, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

Neuroimaging data on functional connections in the brain are frequently represented by weighted networks. These networks share the same set of labeled nodes corresponding to a fixed atlas of the brain, while each subject’s network has their own edge weights. This thesis focuses on developing statistical tools for analyzing samples of weighted networks with applications to neuroimaging.

We first propose a method for modeling such brain networks via linear mixed effects models, which takes advantage of the community structure, or functional regions, known to be present in the brain. The model allows for comparing two populations, such as patients and healthy controls, globally, at functional systems level, and at individual edge level, with systems-level inference in particular allowing for a biologically meaningful interpretation. We incorporate correlation between edge weights into the model by allowing for a general variance structure, and show this leads to much more accurate inference. A thorough study comparing schizophrenics to healthy controls illustrates the full potential of our methods, and obtains results consistent with the medical literature on schizophrenia.

While we focus on networks as the main object of analysis, auxillary information about subjects is frequently available. The subject’s age is a particularly important covariance, since studying how the brain changes over time can lead to insights about brain development in children and adolescents and the effects of aging for older subjects. A typical neuroimaging study, however, is cross-sectional rather than longitudinal, meaning we measure subjects of many different ages, but only once. We developed two methods for analyzing such samples of multiple, time-stamped networks. One is a parametric approach utilizing a linear mixed effects model with age included as a covariate; the other one is a nonparametric method which can be viewed as a network version of principal component analysis, where we look for components that explain age-related trends and vary smoothly with age. Both approaches take network community structure into account and allow for concise and interpretable representation of the data by obtaining developmental curves for functional regions of the brain that vary smoothly with age. We apply the methods to fMRI data of subjects who are 8 to 22 years old, and extract developmental curves consistent with the current understanding of brain maturation in neuroscience.

Clustering is of special interest in neuroimaging studies of mental illness, because psychiatrists believe that many psychiatric conditions present in multiple distinct and not yet identified subtypes. Clustering brain connectivity networks of patients with a certain disorder can lead to discovering these subtypes, and ideally identifying the differences in connectivity patterns that distinguish between subtypes. Clustering with a large number of features is challenging in itself, and the network nature of the observations presents additional difficulties. Our goal is to develop a clustering method that respects the network nature of the data, allows for feature selection, and scales well to high dimensions. One general method for clustering and feature selection in high dimensions is sparse K-means, which performs feature selection by minimizing the K-means objective function plus a lasso penalty. Here we develop network-aware sparse K-means, using a network-induced penalty for simultaneously clustering weighted networks and performing feature selection. We also develop a Gaussian mixture model version of the algorithm, particularly useful when features are highly correlated, which is the case in neuroimaging. We illustrate the method on simulated networks and an fMRI dataset of youth.

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Other Tue, 16 Jul 2019 14:23:52 -0400 2019-05-15T10:00:00-04:00 2019-05-15T12:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Physics Graduate Student Symposium (PGSS) | Quantum Oscillations in Electrical Resistivity in Kondo Insulators (May 16, 2019 12:00pm) https://events.umich.edu/event/63620 63620-15816694@events.umich.edu Event Begins: Thursday, May 16, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

In metals, orbital motions of conduction electrons on the Fermi surface are quantized in magnetic fields, which is manifested by quantum oscillations in electrical resistivity. This Landau quantization is generally absent in insulators. Here we report a notable exception in an insulator — ytterbium dodecaboride (YbB12). The resistivity of YbB12exhibits distinct quantum oscillations despite having a much larger magnitude than in metals [1]. This unconventional oscillation is shown to arise from the insulating bulk, even though the temperature dependence of the oscillation amplitude follows the conventional Fermi liquid theory of metals. The large effective masses indicate the presence of a Fermi surface consisting of strongly correlated electrons. Quantum oscillations are also observed in the magnetization of YbB12 [1]. Our result reveals a mysterious dual nature of the ground state in YbB12: it is both a charge insulator and a strongly correlated metal.

[1] Z. xiang et al., Science 362, 65 (2018).

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Lecture / Discussion Tue, 14 May 2019 15:03:22 -0400 2019-05-16T12:00:00-04:00 2019-05-16T13:00:00-04:00 West Hall Department of Physics Lecture / Discussion West Hall
Special Astronomy/Physics Seminar | Tidal Stellar Streams as Probes of Dark Matter: Detection and Dynamical Analysis (May 20, 2019 12:00pm) https://events.umich.edu/event/63696 63696-15824935@events.umich.edu Event Begins: Monday, May 20, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

Tidal stellar streams have gained a lot of popularity in the field of astrophysics. These orbit-like structures, that are formed by the tidal disruption of a globular cluster or a satellite galaxy by the potential of the host galaxy, serve as “fossils” that encode information regarding the accretion history of our Galaxy. Recently, it has also been realized that analysis of the morphology and dynamics of star streams provide powerful means to constrain the Milky Way’s gravitational potential and its dark matter distribution, and can also be useful in probing the very nature of the dark matter particle itself.

The talk is intended to provide a short introduction on “stellar stream” systems and their importance in various scientific studies. The other highlight of the talk would be the STREAMFINDER algorithm (an algorithm designed to detect stellar streams in the astrophysical catalogues) and the new panoramic sky map of the stellar streams of the Milky Way halo that we obtained by analyzing ESA/Gaia DR2. Towards the end, I will also mention some of the recent studies that I have been involved in which also employ stellar streams.

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Workshop / Seminar Wed, 15 May 2019 16:28:20 -0400 2019-05-20T12:00:00-04:00 2019-05-20T13:00:00-04:00 West Hall Department Colloquia Workshop / Seminar West Hall
Dissertation Defense: Group Sparsity in Regression and PCA (May 20, 2019 1:00pm) https://events.umich.edu/event/63733 63733-15839172@events.umich.edu Event Begins: Monday, May 20, 2019 1:00pm
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

In the field of high-dimensional statistics, it is commonly assumed that only a small subset of the variables are relevant and sparse estimators are pursued to exploit this assumption. Sparse estimation methodologies are often straightforward to construct, and indeed there is a full spectrum of sparse algorithms covering almost all statistical learning problems. In contrast, theoretical developments are more limited and often focus on asymptotic theories. In applications, non-asymptotic results may be more relevant.

The goal of this work is to show how non-asymptotic statistical theory can be developed for sparse estimation problems that assume group sparsity. We discuss three different problems: principal component analysis (PCA), sliced inverse regression (SIR) and multivariate regression. For PCA, we study a two-stage thresholding algorithm and provide theories that go beyond the common spiked-covariance model. SIR is then related to PCA in some special settings, and it is shown that the theory of sparse PCA can be modified to work for SIR. Regression represents another important research direction in high-dimensional analysis. We study a linear regression model in which both the response and predictors are grouped, as an extension of group Lasso.

Despite the distinctions in these problems, the proofs of consistency and support recovery share some common elements: concentration inequalities and union probability bounds, which are also the foundation of most existing sparse estimation theories. The proofs are presented in modules in order to clearly reveal how most sparse estimators can be theoretically justified. Moreover, we identify those modules that are possibly not optimized to show the limitation of the existing proof techniques and how they could be extended.

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Other Tue, 16 Jul 2019 14:23:24 -0400 2019-05-20T13:00:00-04:00 2019-05-20T15:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Dissertation Defense: Large Data Approaches to Thresholding Problems (May 22, 2019 10:30am) https://events.umich.edu/event/64296 64296-16282455@events.umich.edu Event Begins: Wednesday, May 22, 2019 10:30am
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

Advances in computational hardware has greatly expanded the power to collect and store data. With collection of greater data sets, comes greater difficulties in estimation, warranting more analysis and novel methods to handle. This is still true in threshold estimation, the estimation of discontinuities. To this end we present this body of work in thresholding problems in long data sequences and data with growing dimensions. The former setting, more commonly known as the change point problem, we introduce and analyze a method which can estimate change points with greater computational efficiency than existing procedures, without compromising the accuracy of the estimators. For the latter problem, also known as the change plane problem, we will study the case when the dimension of the problem grows with the sample size, a setting not well-studied in existing literature, and lay the groundwork with asymptotic results.

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Other Tue, 16 Jul 2019 14:21:22 -0400 2019-05-22T10:30:00-04:00 2019-05-22T12:30:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Physics Graduate Student Symposium (PGSS) | Status on the Search for the Rare Kaon Decay, K_L→ π^0νν (May 23, 2019 12:00pm) https://events.umich.edu/event/63737 63737-15841200@events.umich.edu Event Begins: Thursday, May 23, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

The KOTO experiment at the J-PARC research facility in Tokai, Japan aims to observe and measure the rare decay of the neutral kaon, K_L→π^0νν. This decay has a very small Standard Model predicted branching ratio of 3 x 10^{-11} which is why it has never been experimentally observed. While this decay is extremely rare, it is one of the best decays for studying charge-parity violation, which can tell us about the matter and antimatter asymmetry that we see in the universe today. In this talk, I will explain the details of how KOTO searches for this rare decay and present new results from the collaboration published in January 2019 as well as preliminary results from the current analysis.

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Workshop / Seminar Fri, 17 May 2019 14:59:05 -0400 2019-05-23T12:00:00-04:00 2019-05-23T13:00:00-04:00 West Hall Department Colloquia Workshop / Seminar West Hall
GusFest (May 24, 2019 9:00am) https://events.umich.edu/event/64733 64733-16436935@events.umich.edu Event Begins: Friday, May 24, 2019 9:00am
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

LOC Chair Dragan Huterer

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Conference / Symposium Tue, 20 Aug 2019 13:32:29 -0400 2019-05-24T09:00:00-04:00 2019-05-24T22:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Conference / Symposium West Hall
Special HEP-Astro Seminar | Super Tau Charm Factory(STCF): A Precision Frontier for Particle Physics (May 28, 2019 10:30am) https://events.umich.edu/event/63638 63638-15824835@events.umich.edu Event Begins: Tuesday, May 28, 2019 10:30am
Location: West Hall
Organized By: Department of Physics

A e^+e^-collider that covers the center of mass energy of 2-7 GeV and has a luminosity of 10^{35} cm^{-2} s^{-1} could produce billions of charmonia, charmed baryon pairs and tau lepton pairs right at their production thresholds, which could be the unique data for systematically study physics with Charm quark and tau lepton, in particular the study of the hadron structure, search for exotic hadrons like glueball, hybrid and multi-quark-states, as well as new physics that is beyond the Standard Model through high precision measurements. This presentation will briefly introduce the STCF, mainly its physics motivation, the conception design of the machine and detector, as well as its current status of the project promotion in the world.

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Workshop / Seminar Tue, 28 May 2019 18:15:23 -0400 2019-05-28T10:30:00-04:00 2019-05-28T11:30:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Dissertation Defense: Local Structure of Random Fields - Properties and Inference (May 28, 2019 1:00pm) https://events.umich.edu/event/63807 63807-15890343@events.umich.edu Event Begins: Tuesday, May 28, 2019 1:00pm
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

Advances in data collection and computation tools popularize localized modeling on temporal or spatial data. Similar to the connection between derivatives and smooth functions, one approach to studying the local structure of a random field is to look at the tangent field, which is a stochastic random field obtained as a limit of suitably normalized increment of the random field at any fixed location. This thesis develops theories for tangent fields of any order and new statistical tools for their inference.

Our first project focuses on various properties of tangent fields. In particular, we show that tangent fields are self-similar and intrinsically stationary. Those two properties, along with the assumption of mean-square continuity, allow us to fully characterize a tangent field via a spectral representation, which provides a systematic way to obtain useful models. Our extension of the spectral theory to abstract spaces, including function spaces, can be of interest on its own. We also connect our theories with common models in spatial statistics including the Mat\'ern model and its variations. Preliminary inference methods are proposed along with simulation studies.

An important example of random fields with tangent fields is the multifractional Brownian motion which has been studied extensively. Our second project focuses on a wide range of issues concerning the estimation of the Hurst function of a multifractional Brownian motion when the process is observed on a regular grid. A theoretical lower bound for the minimax risk of this inference problem is established for a wide class of smooth Hurst functions. We also propose nonparametric estimators and show they are rate optimal. Implementation issues including how to overcome the presence of a nuisance parameter and choose the tuning parameter from data have also been included. An extensive numerical study is conducted to compare our approach with other approaches. Some explorations about nongrid observations and nonconstant variances are also included.

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Other Tue, 16 Jul 2019 14:22:57 -0400 2019-05-28T13:00:00-04:00 2019-05-28T15:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Special Astronomy Talk | The Southern Stellar Stream Spectroscopic Survey (S5) (June 13, 2019 3:00pm) https://events.umich.edu/event/63945 63945-16033412@events.umich.edu Event Begins: Thursday, June 13, 2019 3:00pm
Location: West Hall
Organized By: Astronomy Colloquia

Recently, more than a dozen new stellar streams in the Milky Way were discovered in the southern hemisphere with the Dark Energy Survey (DES). In this talk, I will present an ongoing spectroscopic program S5, which maps these southern streams with the 2df/AAOmega spectrograph on the Anglo-Australian Telescope. S5 is the first systematic program pursuing a complete census of known streams in the southern hemisphere. The radial velocities and stellar metallicities from S5, together with the proper motions from Gaia DR2, provide a unique sample to understand the Milky Way halo populations, the progenitors and formation of the streams, the mass and shape of the Milky Way potential, and to test the characteristics of dark matter. So far, the S5 program has obtained the 6D+1 (metallicity) phase space information for 10 streams in the DES footprint, all of which are the first-time measurements for these southern streams, and we are expanding our program beyond the DES footprint to cover more southern streams. I will give an overview of the S5 program, including target selection, observation, and data analysis, and I will end with a discussion of the implications of the preliminary results from S5.

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Workshop / Seminar Mon, 10 Jun 2019 08:37:53 -0400 2019-06-13T15:00:00-04:00 2019-06-13T16:00:00-04:00 West Hall Astronomy Colloquia Workshop / Seminar West Hall
Physics Graduate Student Symposium (PGSS) | Rapid Scanning AOM Modulation-Based Linear Measurements to Derive the Linear Absorption Spectra of Purple Bacteria (July 11, 2019 12:00pm) https://events.umich.edu/event/64208 64208-16212196@events.umich.edu Event Begins: Thursday, July 11, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

Photosynthesis is a vital process that forms the basis of most life and energy sources on the planet. The knowledge of the underlying mechanisms of charge and energy transfer involved in this process can be used to develop artificial light-harvesting systems and biofuels, helping us to meet our own energy needs. In this talk, I will discuss how we use fluorescence-detection-based two-dimensional electronic spectroscopy (F-2DES) to study the energy transfer in light-harvesting (LH2, in particular) complexes present in photosynthetic purple bacteria. Due to long acquisition times, photobleaching effects during the 2D measurements can distort the features of the acquired spectra. Motivated by the desire to reduce these effects without sacrificing the signal-to-noise ratio (SNR), we have adapted a rapid-scanning approach to record the linear spectra of the complexes in question. I will discuss the technique and results from the same. Extending this rapid-scanning technique to F-2DES promises reduced acquisition times and improved SNR for the 2D spectra.

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Conference / Symposium Fri, 19 Jul 2019 08:50:54 -0400 2019-07-11T12:00:00-04:00 2019-07-11T13:00:00-04:00 West Hall Department Colloquia Conference / Symposium West Hall
Dissertation Defense: Subgroup Analysis: Risk Quantification and Debiased Inference (July 16, 2019 2:00pm) https://events.umich.edu/event/64297 64297-16282456@events.umich.edu Event Begins: Tuesday, July 16, 2019 2:00pm
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

Subgroup analysis is frequently used to account for the treatment effect heterogeneity in clinical trials. When a promising subgroup is selected from existing trial data, a decision on whether an additional confirmatory trial for the selected subgroup is worth pursuing needs to be made. Unfortunately, the usual statistical analysis applied to the selected subgroup as if the subgroup is identified independently of the data often leads to overly optimistic evaluations. Any statistical analysis that ignores how the subgroup is selected tends to suffer from subgroup selection bias. In this dissertation, we propose two new statistical tools to evaluate the selected subgroup. The first is a risk index which can be used as a simple screening tool to reduce the risk of over-optimism in naive subgroup analysis and the second is debiased inference to answer the question of how good the selected subgroup really is. The proposed tools are model-free, easy-to-implement and adjust for the subgroup selection bias appropriately. We demonstrate the merit of the proposed tools by re-analyzing the MONET1 trial. An extension of the debiased inference method is also discussed for observational studies with potentially many confounders.

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Other Tue, 16 Jul 2019 14:06:33 -0400 2019-07-16T14:00:00-04:00 2019-07-16T16:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
A Phase Transition in Network Community Inference (July 18, 2019 12:00pm) https://events.umich.edu/event/64251 64251-16266505@events.umich.edu Event Begins: Thursday, July 18, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

Decomposing a network into communities (a partition of the vertices such that there is a significantly higher density of connections within groups than between groups) has been a subject of great interest in the network science community due to its numerous applications in data compression and machine learning. For many real networks, however, we do not know the "true" community labels, and so one way of assessing whether a community detection algorithm works well or not is to frame the task as an inference problem: there is a set of nodes with artificially assigned "ground truth" community labels, from which a network is created through some probabilistic generative process, and the goal is to recover this structure using only the network and the algorithm of interest. Intuitively, if a graph is too sparsely connected or it is generated from a noisy process, we should fail to recover partitions that are correlated with our artificial ground truth. In this talk I discuss an interesting phenomenon in which it suddenly (in terms of a control parameter) becomes impossible to recover the true communities in a graph, even when they are explicitly planted in its topology! This abrupt qualitative change in the difficulty of the community detection problem is characterized by a phase transition analogous to that in a generalized Potts model in statistical mechanics, which can be derived from a statistical physics perspective using a free energy approximation and the cavity method. I will also discuss future work in this area and its implications for nonconvex optimization.

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Workshop / Seminar Tue, 09 Jul 2019 09:33:02 -0400 2019-07-18T12:00:00-04:00 2019-07-18T13:00:00-04:00 West Hall Department Colloquia Workshop / Seminar West Hall
Constraining Neutrino Properties with the Cosmic Microwave Background (July 25, 2019 12:00pm) https://events.umich.edu/event/64422 64422-16346367@events.umich.edu Event Begins: Thursday, July 25, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

Neutrinos are one half of the leptons included in the standard model of particle physics yet some of their properties are the most poorly constrained aspects of the standard model. Neutrinos are also important in the cosmological standard model due to their suppression of the growth of structure at small angular scales and their influence on the evolution of early universe. The cosmic microwave background (CMB) is one of the best probes we have at observing the effects of neutrinos on the growth of large scale structure and by observing those effects we in turn can place tight constraints on two elusive properties of neutrinos, the sum of their masses and the number of different species. In my talk I’ll introduce both properties of the neutrino and the CMB, the effects neutrinos have on large scale structure that leave imprints on the CMB, current and future missions to observe those effects, and my experimental contributions to those missions.

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Workshop / Seminar Fri, 19 Jul 2019 08:51:33 -0400 2019-07-25T12:00:00-04:00 2019-07-25T13:00:00-04:00 West Hall Department Colloquia Workshop / Seminar West Hall
The Spin Polarization History Mystery; or, History-Dependent Dynamic Nuclear Polarization in Gallium Arsenide (August 1, 2019 12:00pm) https://events.umich.edu/event/64674 64674-16426866@events.umich.edu Event Begins: Thursday, August 1, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

Electron spin has great potential for use in electronic device applications. To that end, our research group focuses on using optical pump-probe techniques to study electron spin dynamics in semiconductor materials. My current project began with an observation of an unexpected dependence of electron spin polarization in gallium arsenide on external magnetic field history. In this talk, I will recount this mystery and how we have set out to solve it. Join me as we search for clues and interrogate the prime suspect, dynamic nuclear polarization. Along the way, I will introduce the key concepts vital to understanding our experiments. Together, we will unravel the mystery of an unexpected spin phenomenon in gallium arsenide as I present a tale of intrigue and spin dynamics.

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Conference / Symposium Mon, 29 Jul 2019 08:26:56 -0400 2019-08-01T12:00:00-04:00 2019-08-01T13:00:00-04:00 West Hall Department Colloquia Conference / Symposium West Hall
Physics Graduate Student Symposium | High Performance Micro-Sensors for Navigation-Grade MEMS Gyroscope (August 15, 2019 12:00pm) https://events.umich.edu/event/65037 65037-16507308@events.umich.edu Event Begins: Thursday, August 15, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

GPS navigation is commonly used in many applications including defense, autonomous vehicles, and robotics. However, absolute dependence on GPS is unreliable due to its limited reachability and susceptibility to interference. For example, a jammer or even a simple and cheap device can be used to spoof GPS signal. As a result, for navigation of high-end vehicles like that of defense and military, one can’t rely entirely on GPS. To make navigation more secure and reliable, inertial sensors are used for navigation when GPS signal is unavailable. Inertial sensors consist of primarily three accelerometers and three gyroscopes in the three perpendicular axes to measure acceleration (or velocity or position) or rate (or angle) of rotation respectively for navigation. Gyroscopes are used to measure the rotation rate and angle of rotation with high precision. Commercial gyroscopes which are used in commercial flights as well as space missions are very precise in their measurement. However, their large sizes, high costs and power requirements limit their use in many applications.

MEMS or Microelectromechanical systems consists of a range of mechanical structures which can be used for various applications. They have an inherent advantage of low cost (C), weight (W), size (S) and power (P) or low CWSaP. They, however, are limited in performance due to large noise. This is a major hurdle which has been limiting the entry of MEMS inertial sensors in navigation-grade performance applications. Our research is focused on bridging this gap and making an ultra-low noise MEMS gyroscope using the microfabrication technologies.

In this talk, I will talk about the design and fabrication of miniaturized 3D shell resonators for gyroscopes. These resonators have exhibited quality factor as high as 10 million leading to very low noise gyroscope at their small size. The achieved performance matrices would enable the use of MEMS sensors as a navigation-grade gyroscope at a cost lower by several orders of magnitude than the existing commercial gyroscopes. Only this would enable each one of us to own a self-driving car and autonomous robots at our homes!

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Conference / Symposium Thu, 08 Aug 2019 10:59:38 -0400 2019-08-15T12:00:00-04:00 2019-08-15T13:00:00-04:00 West Hall Department Colloquia Conference / Symposium West Hall
Dissertation Defense: Unified Price Indices for Spatial Comparisons (August 16, 2019 8:00am) https://events.umich.edu/event/65067 65067-16509334@events.umich.edu Event Begins: Friday, August 16, 2019 8:00am
Location: West Hall
Organized By: Department of Statistics Dissertation Defenses

This thesis proposes a method to measure fine-grained spatial differences in prices using retail barcode scanner datasets. To avoid conflating spatial price differences with differences in consumer preferences for products sold in each area, it extends the framework proposed by Redding and Weinstein to adjust price indices for product turnover, from the temporal to the spatial context. In this extension, differences in spatial product availability are considered analogous to differences in product availability across time. It describes a method to estimate these "spatial UPI" indices, and the uncertainty associated with these estimates. It then applies this method to compare the food cost of living between different counties within the state of Michigan based on the Nielsen retail scanner database.

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Other Thu, 08 Aug 2019 15:46:49 -0400 2019-08-16T08:00:00-04:00 2019-08-16T10:00:00-04:00 West Hall Department of Statistics Dissertation Defenses Other flyer
Physics Graduate Student Symposium (PGSS) | Miniaturized Frequency Combs Enable Advanced Spectroscopies to Leave the Lab and (Maybe) Enter Orbit (August 22, 2019 12:00pm) https://events.umich.edu/event/65404 65404-16595537@events.umich.edu Event Begins: Thursday, August 22, 2019 12:00pm
Location: West Hall
Organized By: Department Colloquia

Frequency Combs, or pulsed lasers which are capable of emitting many narrow and closely spaced spectral lines (teeth) with fixed phase relationships between adjacent teeth, are an essential tool in precision metrology and spectroscopy. Their usefulness comes from the fact that their entire spectrum can be controlled by just adjusting the time between pulses and the pulse-to-pulse phase slip of their electric field. This means that, using relatively simple control schemes, frequency combs enable the most precise measurements of time and frequency possible, among a plethora of other applications. Typically, however, these light sources are roughly the size of a kitchen table and require the high stability of a lab environment to maintain the controllability of their output. Miniaturized combs exist, in the form of microscopic ring resonators, but these light sources are not very tunable, typically require large and powerful pump lasers to operate, and are expensive to manufacture. These drawbacks are all showstoppers when it comes to allowing frequency comb enabled precision measurement and spectroscopy to leave the lab. We have demonstrated a new, extremely cheap, simple, and low power laser diode-based frequency comb which is roughly the size of a grain of rice. This laser can be battery powered, and its spectrum is highly controllable, making it an ideal light source to allow advanced precision measurement and spectroscopy to leave the lab. In my talk, I will give a brief overview of frequency comb-based measurements, demonstrate the stability and tunability of our new sources, and outline their prospect for future ground- and space-based applications.

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Conference / Symposium Mon, 19 Aug 2019 08:51:15 -0400 2019-08-22T12:00:00-04:00 2019-08-22T13:00:00-04:00 West Hall Department Colloquia Conference / Symposium West Hall
Special Physics Colloquium | State of Department Address (September 4, 2019 4:00pm) https://events.umich.edu/event/65753 65753-16651991@events.umich.edu Event Begins: Wednesday, September 4, 2019 4:00pm
Location: West Hall
Organized By: Department Colloquia

Physics Professor and Chair David Gerdes will welcome faculty, staff, and students to the 2019-20 school year and talk about different aspects of the Physics Department.

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Presentation Mon, 26 Aug 2019 12:00:36 -0400 2019-09-04T16:00:00-04:00 2019-09-04T17:00:00-04:00 West Hall Department Colloquia Presentation West Hall
CM Theory Seminar | Gate-Accessible Superconductivity and Helical Modes in Monolayer WTe_2 (September 5, 2019 4:00pm) https://events.umich.edu/event/65277 65277-16565496@events.umich.edu Event Begins: Thursday, September 5, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Quantum materials research aims to uncover exotic physics and new approaches toward applied technologies. Two-dimensional crystals consisting of individual layers of van der Waals materials provide an exciting platform to study correlated and topological electronic states. These same crystals can be flexibly restacked into van der Waals heterostructures, which enable clean interfaces between heterogeneous materials. Such heterostructures enable the isolation and protection of air sensitive 2D materials as well as provide new degrees of freedom for tailoring electronic structure and interactions. In this talk, I will present experimental work studying electronic transport in monolayer WTe_2. First, un-doped monolayer WTe_2 exhibits behaviors characteristic of a 2D topological insulator, including edge mode transport approaching the quantum of conductance up to nearly 100 Kelvin. Second, we have discovered that the same monolayers display superconductivity at low carrier densities accessible by local field-effect gating through a low-κ dielectric. The concurrence of electrostatically accessible superconductor and topological insulator phases in the same 2D crystal allows us to envision a new model of gate-configurable topological electronic devices.

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Workshop / Seminar Thu, 05 Sep 2019 18:16:13 -0400 2019-09-05T16:00:00-04:00 2019-09-05T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Gongjun Xu, Assistant Professor, Department of Statistics, University of Michigan (September 6, 2019 10:00am) https://events.umich.edu/event/63880 63880-15977781@events.umich.edu Event Begins: Friday, September 6, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

Latent class models have wide applications in social and biological sciences. In many applications, pre-specified restrictions are imposed on the parameter space of latent class models, through a design matrix, to reflect practitioners' diagnostic assumptions about how the observed responses depend on the respondents' latent traits. Though widely used in various fields, such restricted latent class models suffer from nonidentifiability due to the models' discrete nature and complex restricted structure. This talk addresses the fundamental identifiability issue of restricted latent class models by developing a general framework for strict and partial identifiability of the model parameters. The developed identifiability conditions only depend on the design matrix and are easily checkable, which provides useful practical guidelines for designing statistically valid diagnostic tests. Furthermore, the new theoretical framework is applied to establish, for the first time, identifiability of several designs from cognitive diagnosis applications.

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Workshop / Seminar Wed, 28 Aug 2019 13:35:05 -0400 2019-09-06T10:00:00-04:00 2019-09-06T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Xu, Gongjun
Quantitative Biology Seminar | Timeseries Analysis of Stochastic Systems with Hidden Components (September 9, 2019 12:00pm) https://events.umich.edu/event/66309 66309-16727886@events.umich.edu Event Begins: Monday, September 9, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Despite dramatic advances in experimental techniques, many facets of intracellular dynamics remain hidden, or can be measured only indirectly. In this talk, I will describe two strategies to analyze stochastic timeseries data from biological systems with hidden parts: replacement of multi-step process with a time delay distribution or quasi-steady-state. Then, I will illustrate how these strategies are applied to understand the processes of protein synthesis, which involves multiple steps such as transcription, translation, folding and maturation, but typically whose intermediates proteins cannot be measured. Furthermore, drugs are also cleared out from our body in multiple steps of metabolism. To estimate the rate of drug clearance, which is a critical factor determining the dose level, a canonical approach has been used in more than 65,000 published papers for last 30 years. I will point out the critical limitation of the canonical approach and propose an alternative approach, which leads to accurate and precise estimation of drug clearance rate.

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Workshop / Seminar Mon, 09 Sep 2019 18:16:27 -0400 2019-09-09T12:00:00-04:00 2019-09-09T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | Intergalactic Medium-based Cosmology: from BOSS to DESI (September 9, 2019 4:00pm) https://events.umich.edu/event/64645 64645-16404981@events.umich.edu Event Begins: Monday, September 9, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Intergalactic Medium (IGM)-based cosmology established itself as a solid cosmological probe with the wide success of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). With the Dark Energy Spectroscopic Instrument (DESI) survey starting imminently, we are taking a look at the accomplishments of SDSS-III with regards to IGM-based cosmology and discussing exciting science and new statistical challenges in the era of DESI.

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Workshop / Seminar Mon, 09 Sep 2019 18:16:27 -0400 2019-09-09T16:00:00-04:00 2019-09-09T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | From Hadrons to Hidden Assumptions: My Recent Work in Quantum Chromodynamics and Foundations of Physics (September 11, 2019 4:00pm) https://events.umich.edu/event/65278 65278-16565497@events.umich.edu Event Begins: Wednesday, September 11, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Two recently initiated directions in my research will be discussed. I will present the first results from a new program at the LHCb experiment at CERN to study hadronization, i.e. how subnuclear particles called quarks and gluons form strong force bound states in quantum chromodynamics. These studies at LHCb over the upcoming decade will drive ideas about how to investigate various hadronization mechanisms further at the future Electron-Ion Collider, proposed for construction in the U.S. in the 2020s. I will additionally give an overview of a project exploring the foundations of physics that aims to find a set of minimal assumptions from which the known laws of physics can be rederived. Pinpointing the conditions under which the different branches of physics are valid should give a better understanding of them and may in turn provide new insights for future theories.

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Workshop / Seminar Wed, 11 Sep 2019 18:16:31 -0400 2019-09-11T16:00:00-04:00 2019-09-11T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM Theory Seminar | Topological and Fractional Electronic States in Graphene Heterostructures (September 12, 2019 4:00pm) https://events.umich.edu/event/66185 66185-16719558@events.umich.edu Event Begins: Thursday, September 12, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Graphene is a highly tunable platform for studying the effects of electron-electron interactions in two dimensions. Encapsulation with a 2D dielectric (hexagonal boron nitride, hBN), and more recently the use of single-crystal graphite top and bottom gates have decreased the electronic disorder to a level suitable for the to study fragile and exotic strongly correlated states. Additionally, control of twist angle between closely-matched crystal lattices allows for unique control of electronic properties, leading to the “Hofstadter butterfly” and more recently unconventional superconductivity. I will describe newly discovered exotic fractional quantum Hall states and a class of related states called fractional Chern insulators, both in high quality graphene heterostructures. These measurements show that graphene is an intriguing platform for realizing new topological and fractional phases, and opens new routes towards realizing interesting quantum phase transitions and manipulating non-abelian quasiparticles for quantum computation.

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Workshop / Seminar Thu, 12 Sep 2019 18:16:34 -0400 2019-09-12T16:00:00-04:00 2019-09-12T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Kengo Kato, Associate Professor, Department of Statistics and Data Science, Cornell University (September 13, 2019 10:00am) https://events.umich.edu/event/63881 63881-15977782@events.umich.edu Event Begins: Friday, September 13, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

In this talk, I will discuss inference for the mean vector of a high
dimensional U-statistic. In the era of Big Data, the dimension of the U statistic and the sample size of the observations tend to be both large, and the computation of the U-statistic is prohibitively demanding. Data-dependent inferential procedures such as the empirical bootstrap for U-statistics is even more computationally expensive. To overcome such computational bottleneck, we introduce randomized incomplete U-statistics with sparse weights whose computational cost can be made independent of the order of the U-statistic. We derive non-asymptotic Gaussian approximation error bounds for the randomized incomplete U-statistics in high dimensions, namely in cases where the dimension is possibly much larger than the sample size, for both non-degenerate and degenerate kernels. In addition, we propose generic bootstrap methods for the incomplete U-statistics that are computationally much less demanding than existing bootstrap methods and establish finite sample validity of the proposed bootstrap methods. If time permits, I will also discuss the extension to infinite order U-statistics.

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Workshop / Seminar Wed, 04 Sep 2019 09:24:45 -0400 2019-09-13T10:00:00-04:00 2019-09-13T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Kato,Kengo
HET Seminar | Aspects of five-dimensional superconformal field theories (September 13, 2019 3:00pm) https://events.umich.edu/event/66678 66678-16770193@events.umich.edu Event Begins: Friday, September 13, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

Five-dimensional superconformal field theories (5d SCFTs) play an interesting role in the general understanding of quantum field theory. They often provide strongly-coupled UV fixed points with remarkable features for perturbatively non-renormalizable gauge theories, which makes them interesting in their own right. Moreover, prominent lower-dimensional theories can be obtained by compactification from five-dimensional parent theories, and this perspective has led to numerous new insights. A fruitful interplay between string theory and quantum field theory methods has led to a coherent and thorough understanding of 5d SCFTs, and I will review recent developments in this context.

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Lecture / Discussion Thu, 12 Sep 2019 14:54:53 -0400 2019-09-13T15:00:00-04:00 2019-09-13T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
HEP-Astro Seminar | A Deep Learning Approach to Galaxy Cluster X-ray Masses (September 16, 2019 4:00pm) https://events.umich.edu/event/64708 64708-16428919@events.umich.edu Event Begins: Monday, September 16, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

I will present a machine-learning approach for estimating galaxy cluster masses from Chandra x-ray mock observations. I will describe how a Convolutional Neural Network (CNN) -- a deep machine learning tool commonly used in image recognition tasks -- can be used to infer cluster masses from these images, reducing scatter in the mass estimates by up to 50%. I will also show an interpretation tool, inspired by Google DeepDream, that can be used to gain some physical insight into what the CNN sees.

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Workshop / Seminar Mon, 16 Sep 2019 18:16:47 -0400 2019-09-16T16:00:00-04:00 2019-09-16T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Controlling Light Matter Interactions in Layered Materials with Conventional and Topological Band Structures (September 17, 2019 4:00pm) https://events.umich.edu/event/66791 66791-16778979@events.umich.edu Event Begins: Tuesday, September 17, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Strongly confined electrical, optical and thermal excitations drastically modify material's properties and break local symmetries that can enable precisely tunable responses and new functionalities. We will discuss the effect of engineered plasmonic lattice on light matter interactions in 2D excitonic crystals to produce novel responses such as enhanced and tunable emission, Fano resonances and strong exciton-plasmon polaritons, which can be precisely controlled by geometry and applied fields to produce new device concepts. Our recent work on collective polaritonic modes and the formation of a complete polaritonic bandgap in few-layered excitonic semiconductors coupled to plasmons will also be presented along with our ability to control them via externally applied electric fields.

We will also discuss our efforts to explore the optoelectronic properties of Mo_x W_{1-x} Te_2, which are type-II Weyl semimetals, i.e., gapless topological states of matter with broken inversion and/or time reversal symmetry, which exhibit unconventional responses to externally applied fields. We have observed spatially dispersive circular photogalvanic effect (s-CPGE) over a wide spectral region (0.2 - 2.0 eV range) in these materials. This effect shows exclusively in the Weyl phase and vanishes upon temperature induced topological phase change. Since the photon energy leads to interband transitions between different electronic bands, we use the density matrix formalism to describe the photocurrent response under chiral optical excitation with a spatially inhomogeneous beam. We will discuss how spatially inhomogeneous optical excitation and unique symmetry and band structure of Weyl semimetals produces CPGE in these systems. The effect of band inversion, Berry curvature and asymmetric carrier relaxation in this material system on the s-CPGE signal will also be discussed along with the implications for designing new and unconventional optoelectronic devices.

Short Biography:
Ritesh Agarwal is a Professor in the Department of Materials Science and Engineering at the University of Pennsylvania. He earned his undergraduate degree from the Indian Institute of Technology, Kanpur in 1996, and a master’s degree from the University of Chicago. He received his PhD in physical chemistry from University of California at Berkeley in 2001 researching liquid and protein solvation and photosynthesis via nonlinear optical techniques. After completing his PhD., Ritesh was a postdoctoral fellow at Harvard where he studied the photonic properties of semiconductor nanowires. His current research interests include structural, chemical, optical and electronic properties of low-dimensional systems. Ritesh is the recipient of the NSF CAREER award in 2007, NIH Director’s New Innovator Award in 2010 and the SPIE Nanoengineering Pioneer Award in 2014. In 2017 he became the director of a Multi-University Research Initiative on Phase Change Materials for Photonics, leading a team of six PIs from five universities.

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Workshop / Seminar Tue, 17 Sep 2019 18:17:16 -0400 2019-09-17T16:00:00-04:00 2019-09-17T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Mohamad Kazem Shirani Faradonbeh, Postdoctoral Researcher, University of Florida (September 17, 2019 4:00pm) https://events.umich.edu/event/66172 66172-16751227@events.umich.edu Event Begins: Tuesday, September 17, 2019 4:00pm
Location: West Hall
Organized By: Department of Statistics

Abstract:
Vector Auto-Regressive (VAR) models are widely used in different applications ranged from econometrics to engineering. The problem of learning the unstable transition matrix of the model is of interest, e.g. for forecasting hyperinflation episodes and stock market bubbles. Especially, a non-asymptotic analysis is required for specifying the roles of sample size, problem dimension, innovation (noise) distribution, and key characteristics of the underlying data generation mechanisms.

In this setting, the Gram matrix of the observed variables randomly diverges, wildly explodes, and is dramatically ill-conditioned. So, the existing approaches based on concentration or mixing time-series are inapplicable. Also importantly, recent studies discovered a new condition for explosive processes that is necessary for accurate learning; being called "regularity" of the transition matrix. In this talk, we present the first set of finite-sample results for the least-squares estimates of the unstable time series with heavy-tailed innovations, and fully quantify the regularity. We also mention novel approaches for studying the "anti-concentration" properties of the underlying random matrices, being used to obtain the presented results.

Further discussions consist of learning the unknown model for planning purposes. That is, designing data-driven input signals which can stabilize the time series, while matrices encoding the evolution of the process and the influence of the input signals, are unknown. The first algorithm for fast stabilization under uncertainty is introduced, with theoretical performance guarantees being established. In order to ensure consistency of estimation, the proposed procedure utilizes two methods of employing random matrices in the design of the exogenous inputs; (i) stochastic feedback, and (ii) stochastic parameter. Numerical examples indicating the effects of both the magnitude and the frequency of the randomizations are provided.

Bio:
Mohamad Kazem Shirani Faradonbeh
is currently a Post-Doctoral Research Associate with the Informatics Institute and the Department of Statistics
at the University of Florida. He received the Ph.D. degree in Statistics from the University of Michigan in 2017, under the supervision of Ambuj Tewari and George Michailidis. Before that, he was an undergraduate student in the Department of Electrical Engineering, Sharif University of Technology. His research interests include sequential statistical analysis, reinforcement learning, data-driven intelligent tutoring, and control of network systems.

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Workshop / Seminar Sat, 07 Sep 2019 09:49:06 -0400 2019-09-17T16:00:00-04:00 2019-09-17T17:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Mohamad Kazem Shirani Faradonbeh
Department Colloquium (September 18, 2019 4:00pm) https://events.umich.edu/event/67172 67172-16805254@events.umich.edu Event Begins: Wednesday, September 18, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

Department Colloquium

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Workshop / Seminar Fri, 13 Sep 2019 16:21:49 -0400 2019-09-18T16:00:00-04:00 2019-09-18T17:00:00-04:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
Department Colloquium | Advancing CMB Cosmology: ACTPol, Simons Observatory, and CMB-S4 (September 18, 2019 4:00pm) https://events.umich.edu/event/65279 65279-16565498@events.umich.edu Event Begins: Wednesday, September 18, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Measurements of the cosmic microwave background (CMB) are a powerful probe of the origin, contents, and evolution of our Universe. CMB measurements continue to improve according to a Moore’s law under which the mapping speed of experiments improves by an order of magnitude roughly every five years. This rapid progression in our ability to measure the CMB has translated into a series of scientific advances including showing our universe to be spatially flat, constraining inflationary and alternative theories of the primordial universe, and providing a cornerstone for our precision knowledge of the Lambda-CDM model. Observations with the current generation of experiments, including Advanced ACTPol, will soon produce improved cosmological constraints. Building on this work, in the coming decade Simons Observatory and ultimately CMB-S4 will: pass critical thresholds in constraints on inflation and light relativistic species; provide improved measurements of dark energy, dark matter, neutrino masses, and a variety of astrophysical phenomena; and enable searches for new surprises.

In this talk I present the design and status of measurements with Advanced ACTPol and how we are building on this work to realize the next generations of experiments including Simons Observatory and CMB-S4. I will highlight the technological advances that underlie the rapid progress in measurements including: polarization sensitive detectors which simultaneously observe in multiple colors; metamaterial antireflection coated lenses and polarization modulators; and overall advances in experimental design. I will present preliminary new results from ACTPol and conclude with science forecasts for the coming decade.

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Workshop / Seminar Wed, 18 Sep 2019 18:17:13 -0400 2019-09-18T16:00:00-04:00 2019-09-18T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM Theory Seminar | Fracton Phase of Matter: From Fantasy to Reality (September 19, 2019 4:00pm) https://events.umich.edu/event/65861 65861-16662139@events.umich.edu Event Begins: Thursday, September 19, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Fracton phase of matter shares many features of topological order, including long-range entangled ground states and non-trivial braiding statistics. At the same time, fracton phase contains subextensive ground-state degeneracy and the restricted mobility of quasiparticle which exclude itself from the TQFT paradigm. In this talk, I will present a theoretical framework on higher rank Chern-Simons theory in 3D as the low energy effective theory for Fracton phases. In addition, I will mention the emergent fractonic phenomenon in plaquette paramagnetic crystal which prompts an algebraic quantum liquid phase with a 'bose Fermi surface'.

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Workshop / Seminar Thu, 19 Sep 2019 18:17:13 -0400 2019-09-19T16:00:00-04:00 2019-09-19T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HET Seminar | The Future Frontier of Higgs Physics (September 20, 2019 3:00pm) https://events.umich.edu/event/67023 67023-16796448@events.umich.edu Event Begins: Friday, September 20, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

I will summarize what we don't already know about the 125 GeV Higgs boson and discuss directions for future investigation.

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Lecture / Discussion Thu, 12 Sep 2019 12:29:25 -0400 2019-09-20T15:00:00-04:00 2019-09-20T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
The Michigan Anthropology Colloquia Series: "Excavating Contentious Muslim-Christian Encounters in Mali" (September 20, 2019 3:00pm) https://events.umich.edu/event/62988 62988-15528500@events.umich.edu Event Begins: Friday, September 20, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"At the dawn of French colonialism, Muslims were a minority among colonial subjects in what is present-day Mali, and Muslim missionaries flourished in the wake of the colonial peace, successfully Islamizing many colonial subjects. Entering this dynamic scene of mass Islamization, the Roman Catholic missionary order, the Missionaires d’Afrique or White Fathers, attempted with little success to bring Catholicism to Muslims and non-Muslims. Drawing on written and archival sources as well as ethnography, the paper focuses on the White Fathers’ mission activities and contentious Muslim-Christian encounters, which have echoes in oral history and the contemporary social imaginary."

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Mon, 16 Sep 2019 12:52:58 -0400 2019-09-20T15:00:00-04:00 2019-09-20T17:00:00-04:00 West Hall Department of Anthropology Lecture / Discussion West Hall
Special AMO Seminar | Quantum Optics with Molecules (September 23, 2019 12:00pm) https://events.umich.edu/event/66867 66867-16781211@events.umich.edu Event Begins: Monday, September 23, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Recent experimental progress in the collective strong coupling regime of organic molecules with optical cavity or plasmonic modes has shown light-induced modifications of material properties. Experimental and theoretical endeavors go in the direction of charge and energy transport, Förster resonance energy transfer (FRET) enhancement, modified chemical reactivity etc. Oftentimes experiments rely on theoretical models developed for standard cavity quantum electrodynamics with two-level quantum emitters. Molecular systems however have an increased complexity as molecular vibrations and level disorder play a crucial role. We provide a theoretical formalism to tackle the light-electronic-vibrations dynamics modeled via the Holstein-Tavis-Cummings Hamiltonian [1]. We analytically describe aspects such as: polariton asymmetry, molecular branching ratio modification in the Purcell regime and cavity-mediated donor-acceptor FRET processes.

[1] M. Reitz, C. Sommer and C. Genes, Langevin approach to quantum optics with molecules, Phys. Rev. Letts 122, 203602 (2019)

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Workshop / Seminar Mon, 23 Sep 2019 18:17:04 -0400 2019-09-23T12:00:00-04:00 2019-09-23T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | Doping Xenon - Performance Enhanced Dark Matter Detectors (September 23, 2019 4:00pm) https://events.umich.edu/event/65417 65417-16597551@events.umich.edu Event Begins: Monday, September 23, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

After a series of null results from the LHC and large direct detection experiments, dark matter remains frustratingly mysterious, and much of the canonical heavy WIMP parameter space is now ruled out. In this talk, I will summarize the current state of the field of dark matter direct detection, and discuss an idea to expand the parameter space that can be probed by large liquid xenon TPCs like the LUX-ZEPLIN (LZ) detector by a adding hydrogen to the target, opening up sensitivity to WIMP masses well below 1 GeV.

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Workshop / Seminar Mon, 23 Sep 2019 18:17:04 -0400 2019-09-23T16:00:00-04:00 2019-09-23T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | From Floquet Real to Imaginary Time Crystal (September 24, 2019 4:00pm) https://events.umich.edu/event/64762 64762-16444919@events.umich.edu Event Begins: Tuesday, September 24, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Quantum time crystal has been an intriguing many-body “time” state that has received much attention and debate since its early prediction. In this talk, first, I will construct a class of concrete “clean” Floquet models to answer the open question on the role of disorder and many-body localization. Second, by observing the equivalent role of the space and imaginary time in the path integral formalism, I will present the finding that hard-core bosons coupled to a thermal bath may exhibit the order of “imaginary spacetime crystal”.

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Workshop / Seminar Tue, 24 Sep 2019 18:17:03 -0400 2019-09-24T16:00:00-04:00 2019-09-24T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium (September 25, 2019 4:00pm) https://events.umich.edu/event/67173 67173-16805255@events.umich.edu Event Begins: Wednesday, September 25, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

Department Colloquium

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Workshop / Seminar Fri, 13 Sep 2019 16:25:04 -0400 2019-09-25T16:00:00-04:00 2019-09-25T17:00:00-04:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
Department Colloquium | New Realms in Coherent Light-Matter Interactions (September 25, 2019 4:00pm) https://events.umich.edu/event/65280 65280-16565499@events.umich.edu Event Begins: Wednesday, September 25, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Light-matter interactions are at the heart of quantum electrodynamics and underpin modern photonic technologies. As we develop means to control the properties of light, matter and their interactions, intriguing new phenomena emerge. Using a designer polariton platform we have developed, we reveal a long sought after Bardeen-Cooper-Schrieffer like phase in a particle-hole-photon strongly-coupled system. Coupling two trapped polariton condensates through both coherent tunneling and incoherent dissipation, we form a model system of rich nonlinear dynamics where new, equidistant frequency lines emerge via the limit cycles at Hopft bifurcation. Using two-dimensional monolayer crystals with exceptionally strong light-matter interactions, we control the exciton-photon interactions from the incoherent limit to the coherent limit with simple mirrors and laser pulses, showing the promise of the system for photonic applications based on coherent light-matter interactions. Combining different monolayers to form atomically-thin heterostructures, we obtain a platform that allows versatile control over both the photon modes and matter excitations, where we create long-lived valley excitons, ultra-thin lasers, and moire-lattice induced hybrid dipolar excitons and polaritons.

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Workshop / Seminar Wed, 25 Sep 2019 18:17:20 -0400 2019-09-25T16:00:00-04:00 2019-09-25T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Michael Woodroofe Lecture Series: Cun-Hui Zhang, Distinguished Professor, Department of Statistics and Biostatistics, Rutgers University (September 27, 2019 10:00am) https://events.umich.edu/event/63882 63882-15977784@events.umich.edu Event Begins: Friday, September 27, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

We consider several problems in areas where Michael Woodroofe has made seminal contributions to. In higher criticism, we develop a one-sided sequential probability ratio test based on the ordered p-values to achieve optimal detection of rare and weak signals. This makes an interesting connection to the test of power one and nonlinear renewal theorem. In multiple isotonic regression, a block estimator is developed to attain minimax rate for a wide range of signal-to-noise ratio, to achieve adaptation to the parametric root-n rate up to a logarithmic factor in the case where the unknown mean is piecewise constant, and to achieve adaptation in variable selection. In uncertainty quantification, we develop second order Stein formulas for statistical inference in nonparametric and high-dimensional problems. Applications of the second order Stein method include exact formulas and upper bounds for the variance of risk estimators and risk bounds for regularized or shape constrained estimators and related degrees of freedom adjustments and confidence regions.

*Hors d'oeuvres immediately following in 337 West Hall (Don Meyer Commons)

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Workshop / Seminar Tue, 24 Sep 2019 09:54:20 -0400 2019-09-27T10:00:00-04:00 2019-09-27T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Zhang,Cun-Hui
Life In Graduate School | Computational Resources at Michigan (September 27, 2019 12:00pm) https://events.umich.edu/event/67234 67234-16828994@events.umich.edu Event Begins: Friday, September 27, 2019 12:00pm
Location: West Hall
Organized By: Life in Graduate School Seminars

Computational Resources at Michigan

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Workshop / Seminar Mon, 16 Sep 2019 09:21:06 -0400 2019-09-27T12:00:00-04:00 2019-09-27T13:00:00-04:00 West Hall Life in Graduate School Seminars Workshop / Seminar West Hall
HET Seminar | Extremal Correlators (September 27, 2019 3:00pm) https://events.umich.edu/event/67551 67551-16892236@events.umich.edu Event Begins: Friday, September 27, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

I will review some of the properties of extremal correlators. I will then describe the large charge limit of some N=2 theories in four dimensions. I will derive a dual random matrix description which admits a ’t Hooft expansion, which is dual to the double scaling limit of the gauge theory. I will compute the analytic and non-analytic terms in the ’t Hooft coupling and give some physical interpretation of the results.

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Lecture / Discussion Mon, 23 Sep 2019 13:31:06 -0400 2019-09-27T15:00:00-04:00 2019-09-27T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
“Mobilizing ‘Blackness’: From the Haitian Revolution to Now” (September 28, 2019 10:00am) https://events.umich.edu/event/66703 66703-16770291@events.umich.edu Event Begins: Saturday, September 28, 2019 10:00am
Location: West Hall
Organized By: Department of Afroamerican and African Studies

From Negritude, to the Anti-Apartheid movement, to Mizrahi Jewish claims to being Black Panthers, to Asian/African/Caribbean coalitions in the United Kingdom, to articulations by German and French youth today, this symposium will address the ways in which “Blackness” has been mobilized to make claims on state and other resources. It will engage the anti-normative forms of living Blackness has enabled. Given these histories and contemporary articulations, it asks: Who can claim Blackness? Under what conditions and with what effect can one make this claim? To what extent does claiming Blackness lead to social change? What are the conditions for coalition around claiming Blackness? Does racism persist, even amongst people of color, in spite of this coalitional claim?

The symposium is free and open to the public and will include a special screening of the documentary Whose Streets? (2018) and the short What Kind of Power Y’All Got (2016) with a Q&A with the filmmakers to follow in Lecture Hall II of the Modern Language Building on Friday, September 27 at 7 PM.

If you have any questions, please contact Damani Partridge (djpartri@umich.edu)

View the schedule online: myumi.ch/zxKNx

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Conference / Symposium Thu, 26 Sep 2019 11:02:40 -0400 2019-09-28T10:00:00-04:00 2019-09-28T13:00:00-04:00 West Hall Department of Afroamerican and African Studies Conference / Symposium Symposium Slider
HEP-Astro Seminar | Status of Belle II (September 30, 2019 4:00pm) https://events.umich.edu/event/66186 66186-16719559@events.umich.edu Event Begins: Monday, September 30, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Belle II and SuperKEKB are the upgrades to the very successful Belle and KEKB B-factory. The goal of this new effort is to increase the data set by a factor of 50 enabling the search for physics beyond the standard model at the intensity frontier. Data taking started in early 2019, and I will describe the new detector and accelerator, give its present status, show some preliminary results, and estimate future prospects.

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Workshop / Seminar Mon, 30 Sep 2019 18:17:18 -0400 2019-09-30T16:00:00-04:00 2019-09-30T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Physics & Astronomy Special Joint Colloquium | Sexual Harassment in STEM: A View from the National Academies (October 1, 2019 3:00pm) https://events.umich.edu/event/66763 66763-16776776@events.umich.edu Event Begins: Tuesday, October 1, 2019 3:00pm
Location: West Hall
Organized By: Department Colloquia

Persistent sexual harassment of women in science has remained a challenge for decades. It jeopardizes progress in closing the gender gap, damages research integrity, and results in a costly loss of talent. In 2016, the National Academies of Sciences, Engineering, and Medicine assembled a committee to conduct a study on this problem. The committee published a comprehensive report in 2018 titled, "Sexual Harassment of Women: Climate, Culture, and Consequences in Academic Sciences, Engineering, and Medicine." The report identifies key findings on the causes and consequences of sexual harassment, and lays out recommendations for institutional policies, strategies, and practices to address and prevent it. U-M Professors Lilia Cortina and Anna Kirkland were two members of that committee. In this talk they will review key findings from the report and discuss implications at the department level.

Please note: Should you require any accommodations to ensure equal access and opportunity related to this event please contact Stacy Tiburzi at 734-764-3440 or stibu@umich.edu.

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Workshop / Seminar Tue, 10 Sep 2019 10:07:37 -0400 2019-10-01T15:00:00-04:00 2019-10-01T16:00:00-04:00 West Hall Department Colloquia Workshop / Seminar West Hall
CM-AMO Seminar | Shedding New Light on Dirac Materials with Nonlinear Optics (October 1, 2019 4:00pm) https://events.umich.edu/event/67592 67592-16900780@events.umich.edu Event Begins: Tuesday, October 1, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Nonlinear optics has recently emerged as an attractive approach for both probing topological properties and driving Dirac materials into new states. Here, I will describe our use of ultrafast nonlinear optics, especially at terahertz (THz) frequencies, to study three representative Dirac materials: graphene micro-ribbons, topological insulators, and Weyl semimetals. We used THz magneto-optical spectroscopy to examine periodic arrays of graphene micro-ribbons, enabling us to control the transmission and Faraday rotation spectra of THz pulses via coupling to discretized magnetoplasmon modes. In the Weyl semimetal TaAs, time-resolved second harmonic generation enabled us to reveal a new photoinduced phase, and THz emission spectroscopy was used to provide new insight into the circular photogalvanic effect. Finally, we used intense THz pulses to drive and coherently control structural dynamics in the topological insulator Bi2Se3. Overall, our studies demonstrate the utility of nonlinear optics in shedding new light on both static and dynamic properties of topological materials.

Biography: Dr. Rohit P. Prasankumar received a B.S. in Electrical Engineering from the University of Texas at Austin in 1997 and the M.S. and Ph.D. degrees in Electrical Engineering from MIT in 1999 and 2003, respectively. His thesis work, completed in 2003, concentrated on developing novel approaches for self-starting mode-locking in solid state lasers. Dr. Prasankumar subsequently performed his postdoctoral research at Los Alamos National Laboratory (LANL), focusing on ultrafast mid-to-far-infrared dynamics in semiconductor nanostructures and strongly correlated compounds. He has been a technical staff member at the Center for Integrated Nanotechnologies (CINT) at LANL since 2006, with research interests principally directed towards the measurement of dynamics in complex materials, such as multiferroics, semiconductor nanowires, and topological materials, with high temporal and spatial resolution over a broad spectral range. He is also a research associate professor at the University of New Mexico.

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Workshop / Seminar Tue, 01 Oct 2019 18:17:13 -0400 2019-10-01T16:00:00-04:00 2019-10-01T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Towards a Better Understanding of the Electroweak Symmetry Breaking Mechanism (October 2, 2019 4:00pm) https://events.umich.edu/event/67174 67174-16805256@events.umich.edu Event Begins: Wednesday, October 2, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

In the Standard Model of particle physics, the massless Goldstone bosons resulting from spontaneous symmetry breaking of the Higgs field became longitudinal components of the W and Z bosons and thus make these vector bosons massive. It is critical to study longitudinal-longitudinal scattering of W and Z bosons at the LHC to validate this electroweak symmetry breaking mechanism and to search for other alternative mechanisms. I will present a few studies that are related to vector boson scattering using data collected by the ATLAS detector. In addition, I will discuss Phase-I and Phase-II upgrade activities of the ATLAS muon spectrometer that my research group has been involved in.

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Workshop / Seminar Fri, 27 Sep 2019 13:57:14 -0400 2019-10-02T16:00:00-04:00 2019-10-02T17:00:00-04:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
Department Colloquium | Towards a Better Understanding of the Electroweak Symmetry Breaking Mechanism (October 2, 2019 4:00pm) https://events.umich.edu/event/65281 65281-16565500@events.umich.edu Event Begins: Wednesday, October 2, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

In the Standard Model of particle physics, the massless Goldstone bosons resulting from spontaneous symmetry breaking of the Higgs field became longitudinal components of the W and Z bosons and thus make these vector bosons massive. It is critical to study longitudinal-longitudinal scattering of W and Z bosons at the LHC to validate this electroweak symmetry breaking mechanism and to search for other alternative mechanisms. I will present a few studies that are related to vector boson scattering using data collected by the ATLAS detector. In addition, I will discuss Phase-I and Phase-II upgrade activities of the ATLAS muon spectrometer that my research group has been involved in.

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Workshop / Seminar Wed, 02 Oct 2019 18:17:18 -0400 2019-10-02T16:00:00-04:00 2019-10-02T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Long Nguyen, Associate Professor, Department of Statistics, University of Michigan (October 4, 2019 10:00am) https://events.umich.edu/event/63883 63883-15977785@events.umich.edu Event Begins: Friday, October 4, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

We study posterior contraction behaviors for parameters of interest in the context of Bayesian mixture modeling, where the number of mixing components is unknown while the model itself may or may not be correctly specified. Posterior contraction rates are given under optimal transport distances for two popular types of prior specification: one requires explicitly a prior distribution on the number of mixture components, and a nonparametric Bayesian approach which places a prior on the space of mixing distributions. Paraphrasing George Box, all mixture models are misspecified, but some may be more interpretable than others — it will be shown that the modeling choice of kernel density functions plays perhaps the most impactful roles in determining the posterior contraction rates in the misspecified situations. Drawing on concrete parameter estimation rates I will highlight some aspects about the interesting tradeoffs between model expressiveness and interpretability that a statistical modeler must negotiate in the rich world of mixture modeling.
This work is joint with Aritra Guha and Nhat Ho.

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Workshop / Seminar Thu, 26 Sep 2019 14:21:24 -0400 2019-10-04T10:00:00-04:00 2019-10-04T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Nguyen,Long
HEP-Astro Seminar | Exploring QCD with Jet Substructure at the LHC (October 7, 2019 4:00pm) https://events.umich.edu/event/67013 67013-16796440@events.umich.edu Event Begins: Monday, October 7, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The inner structure of jets is sensitive to QCD across a wide range of scales, from the perturbative parton shower down to non-perturbative hadronization effects. This information has been used in many searches for distinguishing between different types of jets, but it has been challenging to produce theoretical predictions for these substructure observables due to the presence of non-global logarithms. Recent advances in jet grooming algorithms have made it possible to produce calculations beyond leading logarithmic accuracy for jet substructure observables for the first time at a hadron collider. I will discuss the measurement of the Soft Drop jet mass using data from the ATLAS experiment, which was the first measurement of a substructure observable which could be compared to theoretical predictions beyond leading logarithmic accuracy. I will then discuss the implications of this work, including the possibilities for Monte Carlo tuning as well as measurements of Standard Model parameters.

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Workshop / Seminar Mon, 07 Oct 2019 18:17:20 -0400 2019-10-07T16:00:00-04:00 2019-10-07T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Quantifying the Impact of State-Mixing on the Rydberg Excitation Blockade (October 8, 2019 4:00pm) https://events.umich.edu/event/67614 67614-16902922@events.umich.edu Event Begins: Tuesday, October 8, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The Rydberg excitation blockade, a process in which interactions among highly-excited atoms suppress laser excitation, has been at the heart of an impressive array of recent achievements in quantum information and simulation. It has been shown that state-mixing interactions, which result from couplings among multi particle Rydberg states near Förster resonance, may compromise the effectiveness of the blockade under otherwise favorable conditions [1]. We present progress on an experiment in which we seek to quantify the negative impact of state-mixing on the blockade. We use state-selective field ionization spectroscopy to measure, on a shot-by-shot basis, the distribution of Rydberg states populated during narrowband laser excitation of ultracold rubidium atoms. Our method allows us to quantify both the “mixing-free” blockade effectiveness, as well as the number of additional Rydberg excitations added by each mixing event.

[1] A. Reinhard, et al, PRL, 100, 123007 (2008)

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Workshop / Seminar Tue, 08 Oct 2019 18:17:21 -0400 2019-10-08T16:00:00-04:00 2019-10-08T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Engineering Correlation and Topology in Two-Dimensional Moire Superlattices (October 9, 2019 4:00pm) https://events.umich.edu/event/67175 67175-16805257@events.umich.edu Event Begins: Wednesday, October 9, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

Van der Waals heterostructures of atomically thin crystals offer an exciting new platform to design novel electronic and optical properties. In this talk, I will describe how to engineer correlated and topological physics using moire superlattice in two dimensional heterostructures. I will show that we can realize and control extremely rich condensed matter physics, ranging from correlated Mott insulator and superconductivity to ferromagnetism and topological Chern insulator, in a single device featuring the ABC trilayer graphene and boron nitride moire superlattices.

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Workshop / Seminar Fri, 27 Sep 2019 13:58:52 -0400 2019-10-09T16:00:00-04:00 2019-10-09T17:00:00-04:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
Department Colloquium | Engineering Correlation and Topology in Two-Dimensional Moire Superlattices (October 9, 2019 4:00pm) https://events.umich.edu/event/64804 64804-16446948@events.umich.edu Event Begins: Wednesday, October 9, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Van der Waals heterostructures of atomically thin crystals offer an exciting new platform to design novel electronic and optical properties. In this talk, I will describe how to engineer correlated and topological physics using moire superlattice in two dimensional heterostructures. I will show that we can realize and control extremely rich condensed matter physics, ranging from correlated Mott insulator and superconductivity to ferromagnetism and topological Chern insulator, in a single device featuring the ABC trilayer graphene and boron nitride moire superlattices.

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Workshop / Seminar Wed, 09 Oct 2019 18:17:08 -0400 2019-10-09T16:00:00-04:00 2019-10-09T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Samory Kpotufe, Associate Professor, Department of Statistics, Columbia University (October 11, 2019 10:00am) https://events.umich.edu/event/63884 63884-15977786@events.umich.edu Event Begins: Friday, October 11, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

Abstract:
The problem of transfer and domain adaptation is ubiquitous in machine learning and concerns situations where predictive technologies, trained on a given source dataset, have to be transferred to a new target domain that is somewhat related. For example, transferring voice recognition trained on American English accents to apply to Scottish accents, with minimal retraining. A first challenge is to understand how to properly model the ‘distance’ between source and target domains, viewed as probability distributions over a feature space.

In this talk we will argue that various existing notions of distance between distributions turn out to be pessimistic, i.e., these distances might appear high in many situations where transfer is possible, even at fast rates. Instead we show that some new notions of distance tightly capture a continuum from easy to hard transfer, and furthermore can be adapted to, i.e., do not need to be estimated in order to perform near-optimal transfer. Finally we will discuss near-optimal approaches to minimizing sampling of target data (e.g. sampling Scottish speech), when one already has access to a given amount of source data (e.g. American speech).

This talk is based on some joint work with G. Martinet, and ongoing work with S. Hanneke.

Short-Bio:
Samory Kpotufe is Associate Professor in Statistics at Columbia University. He works in machine learning, with an emphasis on nonparametric methods and high dimensional statistics. Generally, his interests are in understanding basic learning scenarios under practical constraints from modern application domains. He has previously held positions at the Max Planck Institute in Germany, the Toyota Technological Institute at Chicago, and Princeton University.

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Workshop / Seminar Wed, 02 Oct 2019 14:33:27 -0400 2019-10-11T10:00:00-04:00 2019-10-11T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Kpotufe,Samory
Department Colloquium | Quantum Tricks for Detecting Dark Matter Waves (October 16, 2019 4:00pm) https://events.umich.edu/event/65282 65282-16565501@events.umich.edu Event Begins: Wednesday, October 16, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Low mass dark matter manifests as large amplitude classical bosonic waves which exert subtle forces on sensitive experimental apparatus. In conventional experiments, the tiny predicted signals are swamped by the zero-point noise of the quantum vacuum. In this talk, I will describe current research in surpassing the Standard Quantum Limit in readout noise by utilizing the toolboxes of quantum optics, atomic physics, and quantum computing. Topics include the QCD axion and the vanishing neutron electric dipole moment, quantum non-demolition measurements with superconducting qubits and other metamaterials, and stimulated emission with non-classical sensor preparation.

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Workshop / Seminar Wed, 16 Oct 2019 18:17:17 -0400 2019-10-16T16:00:00-04:00 2019-10-16T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Quantum Tricks for Detecting Dark Matter Waves (October 16, 2019 4:00pm) https://events.umich.edu/event/67177 67177-16805258@events.umich.edu Event Begins: Wednesday, October 16, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

Low mass dark matter manifests as large amplitude classical bosonic waves which exert subtle forces on sensitive experimental apparatus. In conventional experiments, the tiny predicted signals are swamped by the zero-point noise of the quantum vacuum. In this talk, I will describe current research in surpassing the Standard Quantum Limit in readout noise by utilizing the toolboxes of quantum optics, atomic physics, and quantum computing. Topics include the QCD axion and the vanishing neutron electric dipole moment, quantum non-demolition measurements with superconducting qubits and other metamaterials, and stimulated emission with non-classical sensor preparation.

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Workshop / Seminar Fri, 27 Sep 2019 14:03:06 -0400 2019-10-16T16:00:00-04:00 2019-10-16T17:00:00-04:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
Statistics Department Seminar Series: Genevera Allen, Associate Professor of Electrical and Computer Engineering, Statistics and Computer Science, Rice University (October 18, 2019 10:00am) https://events.umich.edu/event/63885 63885-15977787@events.umich.edu Event Begins: Friday, October 18, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

Abstract:
Data integration, or the strategic analysis of multiple sources of data simultaneously, can often lead to discoveries that may be hidden in individual analyses of a single data source. In this talk, we present several new techniques for data integration of mixed, multi-view data where multiple sets of features, possibly each of a different domain, are measured for the same set of samples. This type of data is common in heathcare, biomedicine, national security, multi-senor recordings, multi-modal imaging, and online advertising, among others. In this talk, we specifically highlight how mixed graphical models and new feature selection techniques for mixed, mutli-view data allow us to explore relationships amongst features from different domains. Next, we present new frameworks for integrated principal components analysis and integrated generalized convex clustering that leverage diverse data sources to discover joint patterns amongst the samples. We apply these techniques to integrative genomic studies in cancer and neurodegenerative diseases to make scientific discoveries that would not be possible from analysis of a single data set.

Short-Bio:
Genevera Allen is an Associate Professor of Electrical and Computer Engineering, Statistics and Computer Science at Rice University and an investigator at the Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital and Baylor College of Medicine. She is also the Founder and Faculty Director of the Rice Center for Transforming Data to Knowledge, informally called the Rice D2K Lab. Dr. Allen's research focuses on developing statistical machine learning tools to help scientists make reproducible data-driven discoveries. Her work lies in the areas of interpretable machine learning, optimization, data integration, modern multivariate analysis, and graphical models with applications in neuroscience and bioinformatics. Dr. Allen is the recipient of several honors including a National Science Foundation Career award, the George R. Brown School of Engineering's Research and Teaching Excellence Award at Rice University, and in 2014, she was named to the "Forbes '30 under 30': Science and Healthcare" list. Dr. Allen received her PhD in statistics from Stanford University (2010), under the mentorship of Prof. Robert Tibshirani, and her bachelors, also in statistics, from Rice University (2006).

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Workshop / Seminar Thu, 10 Oct 2019 13:56:18 -0400 2019-10-18T10:00:00-04:00 2019-10-18T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Allen
HET Seminar | "Quantum Superposition of Massive Bodies" (October 18, 2019 3:00pm) https://events.umich.edu/event/67321 67321-16837721@events.umich.edu Event Begins: Friday, October 18, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

We analyse a gedankenexperiment previously considered by Mari et al. that involves quantum superpositions of charged and/or massive bodies ("particles'') under the control of the observers, Alice and Bob. In the electromagnetic case, we show that the quantization of electromagnetic radiation (which causes decoherence of Alice's particle) and vacuum fluctuations of the electromagnetic field (which limits Bob's ability to localize his particle to better than a charge-radius) both are essential for avoiding apparent paradoxes with causality and complementarity. We then analyze the gravitational version of this gedankenexperiment. We show that the analysis of the gravitational case is in complete parallel with the electromagnetic case provided that gravitational radiation is quantized and that vacuum fluctuations limit the localization of a particle to no better than a Planck length. This provides support for the view that (linearized) gravity should have a quantum field description.

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Lecture / Discussion Tue, 24 Sep 2019 10:38:08 -0400 2019-10-18T15:00:00-04:00 2019-10-18T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
The Michigan Anthropology Colloquia Series: "Copts and Christian-Muslim Mediation: The Social Life of Theology in Egypt" (October 18, 2019 3:00pm) https://events.umich.edu/event/62987 62987-15528499@events.umich.edu Event Begins: Friday, October 18, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"For Egypt's Coptic Orthodox, image theology is central to mediating human-divine relations. From the Arab uprisings to Sisi's military coup, varying theologies of material imagination have enabled communal critique and minoritarian identification. This talk navigates the social life of theology to understand how visual images organize relations between Christians and Muslims toward national and sectarian ends. In doing so, it considers the communicative aesthetics of religion and the creative making of religious difference within the terms of national unity."

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Tue, 08 Oct 2019 14:54:51 -0400 2019-10-18T15:00:00-04:00 2019-10-18T17:00:00-04:00 West Hall Department of Anthropology Lecture / Discussion West Hall
Complex Systems - Quant. Bio Seminar | Stochastic Turing patterns in oceans, brains and biofilms (October 21, 2019 12:00pm) https://events.umich.edu/event/68409 68409-17080044@events.umich.edu Event Begins: Monday, October 21, 2019 12:00pm
Location: West Hall
Organized By: The Center for the Study of Complex Systems

A special seminar co-hosted by Quantitative Bio. Seminars & CSCS. The first of two talks Professor Goldenfeld will be giving in two days at the University of Michigan

ABSTRACT
Why are the patterns of plankton in the ocean so patchy? Why do frequently described geometrical hallucinations tend to fall into one of four different classes of pattern? Why don't we see hallucinations all the time? And why do populations in ecosystems tend to have noisy cycles in abundance? This talk explains how these phenomena all arise from the discreteness of the underlying entities, be they the on-off states of neurons or the numbers of bacteria in a fluid volume of ocean, or the number of signaling molecules in a biofilm. I explain how tools from statistical mechanics can yield insights into these phenomena, and report on a range of studies that include the operation of the primate visual cortex, the behavior of signalling molecules in a forward-engineered synthetic biofilm, and the fluctuating patterns and populations of marine organisms.

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Workshop / Seminar Tue, 15 Oct 2019 15:45:09 -0400 2019-10-21T12:00:00-04:00 2019-10-21T13:00:00-04:00 West Hall The Center for the Study of Complex Systems Workshop / Seminar Swanlund Professor of Physics Nigel Goldenfeld
Quantitative Biology Seminar | Stochastic Turing Patterns in Oceans, Brains and Biofilms (October 21, 2019 12:00pm) https://events.umich.edu/event/68369 68369-17071276@events.umich.edu Event Begins: Monday, October 21, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Why are the patterns of plankton in the ocean so patchy? Why do frequently described geometrical hallucinations tend to fall into one of four different classes of pattern? Why don't we see hallucinations all the time? And why do populations in ecosystems tend to have noisy cycles in abundance? This talk explains how these phenomena all arise from the discreteness of the underlying entities, be they the on-off states of neurons or the numbers of bacteria in a fluid volume of ocean, or the number of signaling molecules in a biofilm. I explain how tools from statistical mechanics can yield insights into these phenomena, and report on a range of studies that include the operation of the primate visual cortex, the behavior of signalling molecules in a forward-engineered synthetic biofilm, and the fluctuating patterns and populations of marine organisms.



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Workshop / Seminar Mon, 21 Oct 2019 18:17:04 -0400 2019-10-21T12:00:00-04:00 2019-10-21T13:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Special CM-AMO Seminar | Inside Nature Physics (October 21, 2019 2:00pm) https://events.umich.edu/event/68304 68304-17045980@events.umich.edu Event Begins: Monday, October 21, 2019 2:00pm
Location: West Hall
Organized By: Department of Physics

Ever wondered what happens behind the scenes at Nature Research journals? We'll discuss what our editors look for in a paper, how we make our decisions, and some tips for writing papers and navigating the submission and review process. Hopefully there will also be plenty of time for questions and discussion.

Bio: David Abergel is an Associate Editor at Nature Physics. After completing a PhD in 2007, he did postdocs at the University of Manitoba and the University of Maryland, before taking a position at Nordita in Stockholm. His research was in condensed-matter theory, mainly focusing on 2D materials and topological materials. In 2017, he joined Nature Physics and is now a full-time editor.

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Workshop / Seminar Mon, 21 Oct 2019 18:17:04 -0400 2019-10-21T14:00:00-04:00 2019-10-21T15:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | Higgs Boson Decay as a Probe to the Unsolved Mysteries in the Universe: dark energy, dark matter and missing antimatter (October 21, 2019 4:00pm) https://events.umich.edu/event/64425 64425-16348357@events.umich.edu Event Begins: Monday, October 21, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Despite being a remarkably simple theoretical model, the Higgs mechanism is the only known theory that is connected to some of the most profound mysteries in the modern physics: dark energy, dark matter and missing antimatter. Measurements of the Higgs boson decay may shield lights on those open questions. In this talk, I will present a few selective results from the ATLAS experiment on the Higgs boson decays. Namely the first observation of the Higgs boson decay to a pair of b-quarks, which had eluded us for many years despite it is the most probable Higgs decay channel; novel techniques to search for potential new physics using the hardonically decaying Higgs boson, and a first search for singly produced long-lived neutral particle that may be realized via Higgs portal. The talk will mainly focus on general descriptions of the measurements without too much technical details, so that the content is accessible to non experimental particle physicists.

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Workshop / Seminar Mon, 21 Oct 2019 18:17:03 -0400 2019-10-21T16:00:00-04:00 2019-10-21T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Gravitational Waves and Neutron Rich Dense Matter (October 23, 2019 4:00pm) https://events.umich.edu/event/67178 67178-16805259@events.umich.edu Event Begins: Wednesday, October 23, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

In 2017 gravitational waves, oscillations of space-time, were detected from the collision of two neutron stars. This historic event provides new insight into very dense neutron rich matter. We compare these observations to the PREX II experiment. PREX uses parity violating electron scattering to precisely locate the 126 neutrons in 208Pb. Despite differing in size by 18 orders of magnitude, both the Pb nucleus and a neutron star are made of the same neutrons, with the same strong interactions, and have the same equation of state (pressure as a function of density). Therefore, PREX II has important implications for neutron star mergers and the structure of neutron stars.

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Workshop / Seminar Wed, 23 Oct 2019 12:47:34 -0400 2019-10-23T16:00:00-04:00 2019-10-23T17:00:00-04:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
Department Colloquium | Gravitational Waves, Very Dense Matter, and Laboratory Experiments (October 23, 2019 4:00pm) https://events.umich.edu/event/65283 65283-16565502@events.umich.edu Event Begins: Wednesday, October 23, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

In 2017 gravitational waves, oscillations of space-time, were detected from the collision of two neutron stars. This historic event provides new insight into very dense neutron rich matter. We compare these observations to the PREX II experiment. PREX uses parity violating electron scattering to precisely locate the 126 neutrons in 208Pb. Despite differing in size by 18 orders of magnitude, both the Pb nucleus and a neutron star are made of the same neutrons, with the same strong interactions, and have the same equation of state (pressure as a function of density). Therefore, PREX II has important implications for neutron star mergers and the structure of neutron stars.

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Workshop / Seminar Wed, 23 Oct 2019 18:17:02 -0400 2019-10-23T16:00:00-04:00 2019-10-23T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Jie Peng, Professor, Department of Statistics, UC Davis (October 25, 2019 10:00am) https://events.umich.edu/event/63886 63886-15977788@events.umich.edu Event Begins: Friday, October 25, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

Diffusion MRI is an in vivo and non invasive imaging technology that uses water diffusion as a proxy to probe architecture of biological tissues. Diffusion MRI technology has been widely used for white matter fiber tracts reconstruction. It also has many clinical applications in neurodegenerative diseases such as Alzheimer's.
In this talk, We discuss various statistical models for analyzing diffusion MRI data. These models aim to elucidate local (voxel-level) neuronal fiber organizations based on D-MRI measurements, which are in turn used as inputs in tracking algorithms to reconstruct white matter fiber tracts. We focus on their capability in resolving crossing fibers -- a major challenge in diffusion MRI data analysis, and their computational scalability. We also discuss spatial smoothing schemes that leverage information from neighboring brain voxels. These methods are applied to both synthetic experiments and to real D-MRI data from large imaging consortium.

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Workshop / Seminar Wed, 16 Oct 2019 15:19:27 -0400 2019-10-25T10:00:00-04:00 2019-10-25T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Jie Peng
HET Seminar | Two-loop mixed EW-QCD corrections to Drell-Yan lepton pair production (October 25, 2019 3:00pm) https://events.umich.edu/event/68269 68269-17037493@events.umich.edu Event Begins: Friday, October 25, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

Drell-Yan lepton pair production is a key process for precision physics at the Large Hadron Collider. In this talk I will consider the two-loop amplitudes required for the full O(\alpha \alpha_s) corrections to this process and discuss the calculation of the required Feynman integrals. While algebraic linear combinations of the integrals fulfill $\;epsilon$ decoupled differential equations, the symbol letters are provably non-rationalizable. I will show that they can nevertheless be integrated in terms of conventional multiple polylogarithms with algebraic arguments, which allow for fast and stable numerical evaluations.

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Lecture / Discussion Thu, 10 Oct 2019 14:06:55 -0400 2019-10-25T15:00:00-04:00 2019-10-25T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
HEP-Astro Seminar | Lensing and Delensing: Results and Updates from BICEP/Keck and the South Pole Telescope (October 28, 2019 4:00pm) https://events.umich.edu/event/67014 67014-16796441@events.umich.edu Event Begins: Monday, October 28, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Gravitational lensing of the cosmic microwave background (CMB) encodes information from the low-redshift universe. Therefore, its measurement is useful for constraining cosmological parameters that describe structure formation, e.g. Omega_m, sigma_8, and the sum of neutrino masses. In this talk, I will present a measurement of and the cosmological constraints from the CMB lensing potential and its power spectrum using data from the SPTpol 500 deg^2 survey. From the minimum variance combination of the lensing estimators from all combinations of SPTpol temperature and polarization data, we measure the lensing amplitude A_MV = 0.944 \pm 0.058 (Stat.) \pm 0.025 (Sys.), which constitutes the tightest lensing amplitude measurement using ground-based CMB data alone. Restricting to only polarization data, we measure the lensing amplitude A_Pol = 0.906 \pm 0.090 (Stat.) \pm 0.040 (Sys.), which is more constraining then our measurement using only temperature data. As SPT-3G, the successor to SPTpol, and other CMB experiments continue to lower the CMB map noise levels, polarization data will dominate the signal-to-noise of lensing measurements for angular multipoles below at least several hundred. Looking to the future, high signal-to-noise measurements of lensing enabled by deep polarization maps is crucial for constraining the sum of neutrino masses and the amplitude of inflationary gravitational waves through delensing. If time permits, I will give an update on the current effort of delensing the BICEP/Keck telescope data.

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Workshop / Seminar Mon, 28 Oct 2019 18:16:53 -0400 2019-10-28T16:00:00-04:00 2019-10-28T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Many-body Physics of Ultracold Gases in Synthetic Dimensions: from Self-trapping to Quantum Strings (October 29, 2019 4:00pm) https://events.umich.edu/event/68736 68736-17147124@events.umich.edu Event Begins: Tuesday, October 29, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Synthetic dimensions alter one of the most fundamental properties in nature, the dimension of space. They allow, for example, a low-dimensional system to act as effectively higher-dimensional. Experiments on ultracold systems create synthetic dimensions using internal or external degrees of freedom of particles for highly controllable quantum simulation.

We consider two methods to create synthetic dimensions in ultracold gases - momentum states of ultracold atoms, and rotational states of ultracold dipolar molecules. In the atomic system with the momentum-state lattice, which has been realized experimentally in the Gadway group, pairs of Raman lasers drive momentum-state transitions, realizing tunnelings in the synthetic lattice. In the molecular system, microwaves can be used to induce rotational-state transitions, realizing tunnelings in the synthetic lattice which can span hundreds of sites. Both systems can show many-body physics due to strong interactions arising respectively from contact interactions and dipolar interactions. We discuss the many-body physics of these systems, ranging from momentum-dependent self-trapping that has been experimentally observed in the atomic systems, to a novel string phase that is theoretically predicted to occur in the molecular systems.

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Workshop / Seminar Tue, 29 Oct 2019 18:16:50 -0400 2019-10-29T16:00:00-04:00 2019-10-29T17:00:00-04:00 West Hall Department of Physics Workshop / Seminar West Hall
Statistics Department Seminar Series: Heping Zhang, Susan Dwight Bliss Professor of Biostatistics, Professor in the Child Study Center and Professor of Statistics and Data Science, Yale University (November 1, 2019 10:00am) https://events.umich.edu/event/63887 63887-15977789@events.umich.edu Event Begins: Friday, November 1, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

Ordinal outcomes are common in scientific research and everyday practice, and we often rely on regression models to make inference. A long-standing problem with such regression analyses is the lack of effective diagnostic tools for validating model assumptions. The difficulty arises from the fact that an ordinal variable has discrete values that are labeled with, but not, numerical values. The values merely represent ordered categories. In this paper, we propose a surrogate approach to defining residuals for an ordinal outcome Y. The idea is to define a continuous variable S as a ``surrogate'' of Y and then obtain residuals based on S. For the general class of cumulative link regression models, we study the residual's theoretical and graphical properties. We show that the residual has null properties similar to those of the common residuals for continuous outcomes. Our numerical studies demonstrate that the residual has power to detect misspecification with respect to 1) mean structures; 2) link functions; 3) heteroscedasticity; 4) proportionality; and 5) mixed populations. The proposed residual also enables us to develop numeric measures for goodness-of-fit using classical distance notions. Our results suggest that compared to a previously defined residual, our residual can reveal deeper insights into model diagnostics. We stress that this work focuses on residual analysis, rather than hypothesis testing. The latter has limited utility as it only provides a single p-value, whereas our residual can reveal what components of the model are misspecified and advise how to make improvements.

This is a joint work with Dungang Liu, University of Cincinnati Lindner College of Business.

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Workshop / Seminar Wed, 23 Oct 2019 12:43:56 -0400 2019-11-01T10:00:00-04:00 2019-11-01T11:00:00-04:00 West Hall Department of Statistics Workshop / Seminar Heping Zhang
HET Seminar | Constraining higher-order gravities with subregion duality (November 1, 2019 3:00pm) https://events.umich.edu/event/68796 68796-17153399@events.umich.edu Event Begins: Friday, November 1, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

In higher derivative theories, gravity can propagate faster or slower than light. This fact has consequences for holographic constructs in AdS/CFT. In this talk, I will focus on the causal and entanglement wedges. I will argue that, in higher derivative theories, these wedges should be constructed using the fastest mode instead of null rays. I will show that using this proposal, the property of causal wedge inclusion, i.e. the fact that the causal wedge must be contained in the entanglement wedge, leads to more stringent constraints on the couplings than those imposed by hyperbolicity and boundary causality. I will elaborate on the implications of these results.

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Lecture / Discussion Thu, 24 Oct 2019 09:03:06 -0400 2019-11-01T15:00:00-04:00 2019-11-01T16:00:00-04:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
The Michigan Anthropology Colloquia Series: "Dating Iroquoia: Refined time frames for coalescence, conflict, and early European influences in northeastern North America" (November 1, 2019 3:00pm) https://events.umich.edu/event/63229 63229-15595501@events.umich.edu Event Begins: Friday, November 1, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"Chronologies fundamentally underpin all other aspects of archaeological thought. When our timeframes shift, so to do the chains of inference that underpin our models and narratives. This talk will detail the results to date of the Dating Iroquoia project. It will review some of the most significant implications of our revised radiocarbon chronology for understanding processes of Iroquoian cultural development, including the timing of coalescence and conflict, the onset of historical enmity between the Huron-Wendat and Haudenosaunee, and the processes through which European goods were transmitted, received, or rejected by Iroquoian communities in Ontario and New York State. The results of this project demonstrate not only the utility of AMS dating and Bayesian chronological modelling for overcoming plateaus and reversals in the calibration curve but also for centering Indigenous agency in historical narratives and helping descendants to better understand the life and times of their ancestors."

The Michigan Anthropology Colloquia Series presents speakers on current topics in the field of anthropology

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Lecture / Discussion Mon, 07 Oct 2019 15:35:26 -0400 2019-11-01T15:00:00-04:00 2019-11-01T17:00:00-04:00 West Hall Department of Anthropology Lecture / Discussion West Hall
HEP-Astro Seminar | Exoplanet Systems as Laboratories for Planet Formation (November 4, 2019 4:00pm) https://events.umich.edu/event/64646 64646-16404982@events.umich.edu Event Begins: Monday, November 4, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

With knowledge of thousands of exoplanet systems from the NASA Kepler Mission, we are closer than ever to understanding how planets form. Patterns in exoplanet populations, compositions, and planetary system architectures are already revealing the most common outcomes of planet formation. I will discuss how I use exoplanet systems as laboratories to test theories of planet formation. My work ranges from characterizing broad patterns across many planetary systems to studying individual systems through their transits, transit timing variations, and radial velocities. In the next ten years, we will measure exoplanet multiplicities, orbital periods, masses, radii, eccentricities, inclinations, obliquities, dynamical interactions, atmospheric compositions, and host star properties using a combination of ground-based and space telescopes. These detailed observations of our exoplanet laboratories will allow us to place the solar system in its galactic context.

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Workshop / Seminar Mon, 04 Nov 2019 18:16:25 -0500 2019-11-04T16:00:00-05:00 2019-11-04T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
CM/AMO Seminar | X-ray Vision of Spins, Charges and Orbitals for Understanding Emergent electronic States in Complex Oxides (November 5, 2019 4:00pm) https://events.umich.edu/event/65481 65481-16605627@events.umich.edu Event Begins: Tuesday, November 5, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Many of the most remarkable properties of quantum materials come from the interplay of multiple charge, orbital and spin degrees of freedom. Probing all of these with a single technique is consequently highly desirable. In this talk, I will describe how resonant inelastic x-ray scattering (RIXS) opens up important new possibilities for measuring these degrees of freedom. This includes observing precursor charge density wave correlations in cuprates [1], observing orbital hybridization in iridates [2], and characterizing the spin behavior within the transient state of photo-doped Sr_2IrO_4 [3].

References
1. H. Miao et al., Proc. Natl. Acad. Sci. U.S.A 114, 12430–12435 (2017); H. Miao et al., Phys. Rev. X 8, 011008 (2018); H. Miao et al., Phys. Rev. X 9, 031042 (2019)
2.Y. Wang et al., Phys. Rev. Lett. 122, 106401 (2019)
3. M. P. M. Dean et al., Nature Materials 15, 601-605 (2016); Y. Cao et al., Phil. Trans. R. Soc. A 377: 20170480 (2019)

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Workshop / Seminar Tue, 05 Nov 2019 18:16:20 -0500 2019-11-05T16:00:00-05:00 2019-11-05T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Physics Adventures in Cancer Research: Cell Motility, Signaling, and Metastasis (November 6, 2019 4:00pm) https://events.umich.edu/event/67015 67015-16796442@events.umich.edu Event Begins: Wednesday, November 6, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Struck by the near total absence of physics thinking and methods in biological research, for the last 30 years, the speaker has endeavored to understand certain phenomena utilizing methods that are based on Physics and are applied to the interpretation of complex biological data. She will discuss 3 examples. In conclusion, we will discuss: Are we ready for the Physics laws of Biology?

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Workshop / Seminar Wed, 06 Nov 2019 18:16:15 -0500 2019-11-06T16:00:00-05:00 2019-11-06T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | Physics Adventures in Cancer Research: Cell Motility, Signaling, and Metastasis (November 6, 2019 4:00pm) https://events.umich.edu/event/67179 67179-16805260@events.umich.edu Event Begins: Wednesday, November 6, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

Struck by the near total absence of physics thinking and methods in biological research, for the last 30 years, the speaker has endeavored to understand certain phenomena utilizing methods that are based on Physics and are applied to the interpretation of complex biological data. She will discuss 3 examples. In conclusion, we will discuss: Are we ready for the Physics laws of Biology?

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Workshop / Seminar Wed, 06 Nov 2019 11:37:37 -0500 2019-11-06T16:00:00-05:00 2019-11-06T17:00:00-05:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
CM Theory Seminar | Cyclotron Resonance Spectroscopy of Symmetry Broken States in Monolayer Graphene (November 7, 2019 4:00pm) https://events.umich.edu/event/65284 65284-16565503@events.umich.edu Event Begins: Thursday, November 7, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Cyclotron resonance—the resonant absorption of light by charge carriers in a strong magnetic field—is widely used to measure the effective band mass of (semi-)conducting materials. This works because the CR absorption in systems having a parabolic dispersion—a reasonable description of most materials—is unaffected by inter-particle interactions. An intriguing corollary is that, for instance, in high mobility GaAs heterostructures when the electronic transport shows remarkably complex behavior in the fractional quantum Hall regime, there is still only a single cyclotron resonance peak that is qualitatively little different from a low-mobility device. But: in materials with a linear dispersion such as graphene, this proscription on spectroscopy of interactions does not hold. We have built a dedicated infrared magnetospectroscopy setup for exploring the cyclotron resonance of interacting Dirac systems, and will report progress including an exciting observation of full integer symmetry breaking of the underlying Landau levels in monolayer graphene. We will also discuss plans for `shining light’ on other correlated electron systems.

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Workshop / Seminar Thu, 07 Nov 2019 18:16:20 -0500 2019-11-07T16:00:00-05:00 2019-11-07T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
ROOM CHANGE: Statistics Department Seminar Series: Matthew Stephens, Professor, Departments of Statistics and Human Genetics, University of Chicago (November 8, 2019 10:00am) https://events.umich.edu/event/63888 63888-15977790@events.umich.edu Event Begins: Friday, November 8, 2019 10:00am
Location: West Hall
Organized By: Department of Statistics

Ever since the pioneering work of James and Stein, the normal means model has been the canonical model for illustrating the ideas and benefits of shrinkage estimation, and has been the subject of considerable theoretical study. By comparison, practical applications of the normal means model are relatively rare, and it has generally been overshadowed by methods like L1-regularization as a way of inducing sparsity. Here we argue that this should change: we describe some recently-developed Empirical Bayes ways to solve the normal means model, and describe how they can be applied to induce shrinkage, sparsity and smoothness in a range of practical applications, including False Discovery Rates, non-parametric regression, sparse regression, and sparse principal components analysis or factor analysis.

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Workshop / Seminar Mon, 04 Nov 2019 09:59:05 -0500 2019-11-08T10:00:00-05:00 2019-11-08T11:00:00-05:00 West Hall Department of Statistics Workshop / Seminar Matthew Stephens
Life After Graduate School Seminar | Still a Physicist, But Not How I Originally Expected (November 8, 2019 12:00pm) https://events.umich.edu/event/69026 69026-17215883@events.umich.edu Event Begins: Friday, November 8, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

From experimental HEP, to particle accelerator operations, PET isotope production, and proton beam therapy for treating cancer, my career has differed from what I envisioned years ago. I will share my experience as an example of what one can do with a physics degree after grad school. There is more “out there” than you may think. Questions and discussion will be encouraged.

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Workshop / Seminar Fri, 08 Nov 2019 18:16:44 -0500 2019-11-08T12:00:00-05:00 2019-11-08T13:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
HET Seminars | EDMs and CP-odd nucleon forces (November 8, 2019 3:00pm) https://events.umich.edu/event/68939 68939-17197041@events.umich.edu Event Begins: Friday, November 8, 2019 3:00pm
Location: West Hall
Organized By: Leinweber Center for Theoretical Physics

I will describe two recent papers [in the last stages of preparation]:
1. Paramagnetic EDMs (usually interpreted as electron electric dipole moment)
have seen a lot of experimental progress in the last decade. I evaluate the sensitivity
of electron EDM experiments to hadronic CP-violation, finding an independent limit on
e.g. theta-term at the level of 10^(-8). 2. In the second part of my talk I revisit the question
of CP-odd axion-nucleon vertices, relevant for the searches of the axionic 5th force.

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Lecture / Discussion Tue, 29 Oct 2019 13:59:40 -0400 2019-11-08T15:00:00-05:00 2019-11-08T16:00:00-05:00 West Hall Leinweber Center for Theoretical Physics Lecture / Discussion West Hall
The Michigan Anthropology Colloquia Series: "New face to an old name: Recent fossil discoveries from Woranso-Mille, Afar region, Ethiopia" (November 8, 2019 3:00pm) https://events.umich.edu/event/68429 68429-17080062@events.umich.edu Event Begins: Friday, November 8, 2019 3:00pm
Location: West Hall
Organized By: Department of Anthropology

"Woranso-Mille, a paleoanthropological site located in the Afar region of Ethiopia, has become one of the most important sites to understand the evolutionary history of early hominins during the mid-Pliocene. The geological sequence at this site (~150 meter-thick) samples almost one and a half million years, between >4.3 and <3.0 million years ago (Ma). It is the only site thus far that has provided incontrovertible fossil evidence showing that there were multiple related hominin species co-existing in close geographic proximity during the mid-Pliocene (3.5 – 3.3 Ma). Recently, a 3.8-million-year-old almost complete hominin cranium was discovered at the site and it was assigned to A. anamensis - the earliest known species of the genus Australopithecus – dated to 4.2 – 3.9 Ma. In addition to revealing the face of A. anamensis for the first time, the new cranium also challenged the long-held hypothesis of anagenetic transition from A. anamensis to Lucy’s species, A. afarensis, and added about 100kyr to the younger end of A. anamensis."

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Lecture / Discussion Fri, 01 Nov 2019 12:45:00 -0400 2019-11-08T15:00:00-05:00 2019-11-08T17:00:00-05:00 West Hall Department of Anthropology Lecture / Discussion West Hall
Quantitative Biology Seminar | Experimental Design for Large Scale Virtual Screening (November 11, 2019 12:00pm) https://events.umich.edu/event/68968 68968-17205309@events.umich.edu Event Begins: Monday, November 11, 2019 12:00pm
Location: West Hall
Organized By: Department of Physics

Virtual screening of commercial make-on-demand chemical libraries is a promising strategy for rapid, low-cost drug discovery. However, due to the uncertain predictive accuracy, it is not clear how to best integrate docking into discovery campaigns, an instance of a general problem for applying complex prediction methods. To address this challenge, I will describe how we designed a Bayesian optimal experiment to estimate the hit-rate as a function of predicted free energy of binding by carefully selecting ~500 compounds test in an in vitro binding assay. Using this an example, I will then describe a novel statistical and computational framework for efficiently computing Bayesian optimal designs. The core idea is to use stochastic gradient descent to simultaneously optimize the parameters of variational bounds of the expected information gain and the experimental degrees of freedom. Through implementing this in Pyro a probabilistic programming language built on PyTorch, this method can scale to designing highly informative experiments to calibrate a wide range of predictive models.

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Workshop / Seminar Mon, 11 Nov 2019 18:16:33 -0500 2019-11-11T12:00:00-05:00 2019-11-11T13:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
HEP-Astro Seminar | Searching for Long-lived Particles with Displaced Vertices in ATLAS (November 11, 2019 4:00pm) https://events.umich.edu/event/67016 67016-16796443@events.umich.edu Event Begins: Monday, November 11, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Most searches for new physics at the Large Hadron Collider assume that a new particle produced in pp-collisions decays almost immediately, or is non-interacting and escapes the detector. However, a variety of new physics models that predict particles which decay inside the detector at a discernible distance from the interaction point. Such long-lived particles would create spectacular signatures and evade many prompt searches. In this talk I will focus on a search for long-lived particles in events with a displaced vertex and a muon. I will also discuss challenges for the Muon Spectrometer in the face of increasing LHC luminosity.

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Workshop / Seminar Mon, 11 Nov 2019 18:16:33 -0500 2019-11-11T16:00:00-05:00 2019-11-11T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
CM-AMO Seminar | Playing with a Quantum Toy: Exploring Thermalization Near Integrability with a Magnetic Quantum Newton's Cradle (November 12, 2019 4:00pm) https://events.umich.edu/event/69176 69176-17261053@events.umich.edu Event Begins: Tuesday, November 12, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

Thermalization of near-integrable quantum systems is an unresolved question. We will present a new experiment that explores the emergence of thermalization in a quantum system by studying the dynamics of the momentum in a dipolar quantum Newton's cradle consisting of highly magnetic dysprosium atoms. This system constitutes the first dipolar strongly interacting 1D Bose gas. These interactions provide tunability of both the strength of the integrability-breaking perturbation and the nature of the near-integrable dynamics. The work sheds light on the mechanisms by which isolated quantum many-body systems thermalize and on the temporal structure of the onset of thermalization. We anticipate our novel 1D dipolar gas will yield insights into quantum thermalization and strongly interacting quantum gases with long-range interactions.

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Workshop / Seminar Tue, 12 Nov 2019 18:16:41 -0500 2019-11-12T16:00:00-05:00 2019-11-12T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall
Department Colloquium | KOTO: The Search for the Elusive K_L → πνν (November 13, 2019 4:00pm) https://events.umich.edu/event/69170 69170-17259020@events.umich.edu Event Begins: Wednesday, November 13, 2019 4:00pm
Location: West Hall
Organized By: Undergrad Physics Events

The KOTO experiment at J-PARC aims to help explain why we live in a matter dominant universe. It is believed that Charge-Parity (CP) violation is critical in this asymmetry, and studying where new CP violation can enter beyond the predictions of the Standard Model (SM) is an exciting frontier for discovering new physics.

The KOTO experiment was designed to observe and study the 𝐾_L → 𝜋𝜈𝜈 decay. The Standard Model (SM) prediction for the mode is 3.0 x 10^{-11} with a small theoretical uncertainty [1]. A previous experimental upper limit of 2.6 x 10^{-8} was set by the KEK E391a collaboration [2]. The rare “golden” decay is ideal for probing for physics beyond the standard model. A comparison of experimentally obtained results with SM calculations permits a test of the quark flavor region and provides a means to search for new physics.

The signature of the decay is a pair of photons from the π^0 decay and no other detected particles. For the measurement of the energies and positions of the photons, KOTO uses a Cesium Iodide (CSI) electromagnetic calorimeter as the main detector, and hermetic veto counters to guarantee that there are no other detected particles.

KOTO’s initial data was collected in 2013 and achieved a similar sensitivity as E391a result [3]. Since then, we completed hardware upgrades and had additional physics runs in 2015, 2016- 2018, and earlier this year. This presentation will present the motivation for this study, new results from KOTO [4], and discuss the status of the ongoing search in detecting 𝐾_L → 𝜋𝜈𝜈.

[1] C. Bobeth, A. J. Buras, A. Celis, and M. Jung, J. High Energy Phys. 04, 079 (2017). [2] J. K. Ahn et al., Phys. Rev. D 81, 072004 (2010).
[3] J. K. Ahn et al., Prog. Theor. Phys. 021C01 (2017).
[4] J. K. Ahn et al., Phys. Rev. Lett. 122 no.2, 021802 (2019

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Workshop / Seminar Wed, 06 Nov 2019 11:35:46 -0500 2019-11-13T16:00:00-05:00 2019-11-13T17:00:00-05:00 West Hall Undergrad Physics Events Workshop / Seminar West Hall
Department Colloquium | The Search for the Elusive K_L → πνν with the KOTO Detector (November 13, 2019 4:00pm) https://events.umich.edu/event/69073 69073-17224170@events.umich.edu Event Begins: Wednesday, November 13, 2019 4:00pm
Location: West Hall
Organized By: Department of Physics

The KOTO experiment at J-PARC aims to help explain why we live in a matter dominant universe. It is believed that Charge-Parity (CP) violation is critical in this asymmetry, and studying where new CP violation can enter beyond the predictions of the Standard Model (SM) is an exciting frontier for discovering new physics.

The KOTO experiment was designed to observe and study the 𝐾_L → 𝜋𝜈𝜈 decay. The Standard Model (SM) prediction for the mode is 3.0 x 10^{-11} with a small theoretical uncertainty [1]. A previous experimental upper limit of 2.6 x 10^{-8} was set by the KEK E391a collaboration [2]. The rare “golden” decay is ideal for probing for physics beyond the standard model. A comparison of experimentally obtained results with SM calculations permits a test of the quark flavor region and provides a means to search for new physics.

The signature of the decay is a pair of photons from the π^0 decay and no other detected particles. For the measurement of the energies and positions of the photons, KOTO uses a Cesium Iodide (CSI) electromagnetic calorimeter as the main detector, and hermetic veto counters to guarantee that there are no other detected particles.

KOTO's initial data was collected in 2013 and achieved a similar sensitivity as E391a result [3]. Since then, we completed hardware upgrades and had additional physics runs in 2015, 2016- 2018, and earlier this year. This presentation will present the motivation for this study, new results from KOTO [4], and discuss the status of the ongoing search in detecting 𝐾_L → 𝜋𝜈𝜈.

[1] C. Bobeth, A. J. Buras, A. Celis, and M. Jung, J. High Energy Phys. 04, 079 (2017). [2] J. K. Ahn et al., Phys. Rev. D 81, 072004 (2010).
[3] J. K. Ahn et al., Prog. Theor. Phys. 021C01 (2017).
[4] J. K. Ahn et al., Phys. Rev. Lett. 122 no.2, 021802 (2019

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Workshop / Seminar Wed, 13 Nov 2019 18:16:40 -0500 2019-11-13T16:00:00-05:00 2019-11-13T17:00:00-05:00 West Hall Department of Physics Workshop / Seminar West Hall