Extension of the Generalized Hydrodynamics to the Dimensional Crossover Regime

TL;DR

This paper extends generalized hydrodynamics to quasi-1D cold gas systems by including transverse excitations and collision effects, enabling accurate modeling of thermalization observed in experiments.

Contribution

It introduces a novel extension of integrable hydrodynamics that incorporates transverse excitations and collision integrals for better experimental relevance.

Findings

Captures thermalization rates consistent with experiments

Models quasi-1D condensates with transverse excitations

Extends GHD to include collision effects

Abstract

In an effort to address integrability breaking in cold gas experiments, we extend the integrable hydrodynamics of the 1d Lieb-Liniger model with two additional components representing the population of atoms in the first and second transverse excited states, thus enabling a description of quasi-1d condensates. Collisions between different components are accounted for through the inclusion of a Boltzmann-type collision integral in the hydrodynamic equation. Contrary to standard generalized hydrodynamics, our extended model captures thermalization of the condensate at a rate consistent with experimental observations from a quantum Newton's cradle setup.