Quench Dynamics in Bose condensates in the Presence of a Bath: Theory and Experiment

TL;DR

This paper investigates the transient behavior of a Bose superfluid after an interaction quench, incorporating dissipation via an environmental bath, and compares theoretical predictions with experimental results.

Contribution

It provides an exact solution for the dynamics of a quenched Bose condensate including dissipation, extending beyond mean field theories.

Findings

Derived time-dependent density correlation functions with correct asymptotic behavior.

Observed damping of sound modes consistent with experimental data.

Showed the importance of dissipation in accurately modeling Bose superfluid dynamics.

Abstract

In this paper we study the transient dynamics of a Bose superfluid subsequent to an interaction quench. Essential for equilibration is a source of dissipation which we include following the approach of Caldeira and Leggett. Here we solve the equations of motion exactly by integrating out an environmental bath. We thereby derive precisely the time dependent density correlation functions with the appropriate analytic and asymptotic properties. The resulting structure factor exhibits the expected damping and thereby differs from that of strict Bogoliubov theory. These damped sound modes, which reflect the physics beyond mean field approaches, are characterized and the structure factors are found to compare favorably with experiment.