Generalized HydroDynamics on an Atom Chip*

I will present an experimental test of the new theory of Generalized HydroDynamics (GHD), introduced in 2016 to describe long wave-length dynamics of one-dimensional (1d) quantum integrable systems [1]. Integrable systems posses an infinite number of conserved quantities and GHD takes into account the conservation of all of them. We monitor the time evolution of the in situ density profiles of a single 1d cloud of bosonic atoms trapped on an atom chip after a quench of the longitudinal trapping potential. The weakly interacting atomic clouds lie at the crossover between the quasicondensate and the ideal Bose gas regimes. Predictions of GHD are in very good agreement with the experiment. Previously existing theories such as the “conventional” hydrodynamic approach, which relies on the assumption of local thermal equilibrium, described by a Gibbs ensemble, are unable to reproduce the experimental data. These results can be found in [3].

[1] Dubail, Jérôme. "A more efficient way to describe interacting quantum particles in 1D." Physics 9 (2016): 153.
[3] Schemmer, at al., “Generalized HydroDynamics on an Atom Chip”. arXiv preprint:1810.07170 (2018).