Experiments with nearly-integrable ultracold 1D gases have probed dynamics involving large distances and long times, testing the recently proposed theory of generalized hydrodynamics [1]. Using "high-energy" quenches implemented via a Bragg scattering pulse, the experiments have also unveiled equilibration at the shortest available time scales, a process known as hydrodynamization in the context of relativistic heavy-ion collisions, which precedes local prethermalization [2]. I will discuss the experimental results as well as their theoretical understanding and modeling. For hydrodynamization, I'll argue that near-integrability provides a theoretical framework from which one can draw a general picture that applies to nonintegrable systems.

References:
[1] N. Malvania, Y. Zhang, Y. Le, J. Dubail, MR, and D.S. Weiss, Generalized hydrodynamics in strongly interacting 1D Bose gases, Science 373, 1129 (2021).
[2] Y. Le, Y. Zhang, S. Gopalakrishnan, MR, and D. S. Weiss, Observation of hydrodynamization and local prethermalization in 1D Bose gases, Nature 618, 494 (2023).