Hydrodynamic flow of expanding Bose-Einstein condensates

TL;DR

This paper presents an exact hydrodynamic solution for the expansion of quasi-one-dimensional Bose-Einstein condensates, validated by numerical simulations, and provides insights into the expansion velocity and current density relevant to experiments.

Contribution

It offers a novel exact hydrodynamic solution for BEC expansion and compares it with numerical simulations, enhancing understanding of experimental observations.

Findings

Excellent agreement between hydrodynamic solution and numerical simulation.

Estimation of maximum current density and expansion velocity.

Qualitative understanding of experimental BEC expansion properties.

Abstract

We study expansion of quasi-one-dimensional Bose-Einstein condensate (BEC) after switching off the confining harmonic potential. Exact solution of dynamical equations is obtained in framework of the hydrodynamic approximation and it is compared with the direct numerical simulation of the full problem showing excellent agreement at realistic values of physical parameters. We analyze the maximum of the current density and estimate the velocity of expansion. The results of the 1D analysis provides also qualitative understanding of some properties of BEC expansion observed in experiments.