Zoom link:
https://umich.zoom.us/j/91655313495 with the passcode: CM-AMO

Efficient quantum conversion interface between single photon qubits and local computing qubits is the key to realize large-scale quantum networks and distributed quantum computing. Lacking such interfaces, the existing leading quantum computers platforms, such as superconducting circuits, trapped ions, and neutral atom arrays, are not ready to be connected to quantum networks. On the other side, photonic systems have demonstrated power in solving intractable problems like Boson sampling, but face challenges for practically scalable universal quantum computing because it is extremely difficult for a single photon to control another deterministically. The widely used scheme with linear optics, making use of probabilistic measurement induced effective “nonlinearity”, is practically not efficient for large scale implementation because it requires enormous amount of ancilla photons and computational time. In this talk, we describe a hybrid approach to address this issue with a universal distributed quantum computing scheme based on photonic polarizations and efficient atomic-ensemble ground-state quantum memories (QMs). Single-qubit photonic gate operations can be implemented with linear optics. To introduce nonlinear interaction between two qubits, we convert the photonic qubit states into atomic-ensemble-based QM states and implement two-qubit controlled-phase gate with Rydberg blockade effect. As the quantum circuit elements are spatially distributed and connected via optical modes, this hybrid photon-atom scheme can be used to build a distributed quantum computer. While the current research in quantum computing and networks are nearly isolated and there is a lack of protocol for networking distributed multiple-qubit quantum computers, our scheme provides a natural quantum network interface for cloud quantum computing with remote quantum computers.