Generalized hydrodynamics in strongly interacting quenched 1D Bose gases

The dynamics of strongly interacting quantum many-body systems are notoriously complicated and difficult to simulate. A recently developed theory called generalized hydrodynamics (GHD) promises to simplify calculations for nearly-integrable systems by following the evolution of the distribution of rapidities, which are the momenta of underlying quasiparticles. To test GHD, we initialize bundles of 1D Bose gases in both the strong and intermediate coupling strength regimes. We then perform large trap quenches and directly measure the rapidity distributions as they evolve [1]. We find excellent agreement between the evolution in these experiments and GHD theory for dimensionless coupling parameters that range from 0.3 to 9.3, demonstrating that the approximations intrinsic to GHD apply in many cold-atom experiments. We also measure the 1D momentum distributions after the quench, allowing us to infer the way in which the quasiparticles themselves evolve.

[1] N. Malvania, Y. Zhang, Y. Le, J. Dubail, M. Rigol, and D. S. Weiss, arXiv:2009.06651