Quench Dynamics of Three-Dimensional Disordered Bose Gases: Condensation, Superfluidity and Fingerprint of Dynamical Bose Glass

TL;DR

This paper investigates how disorder affects superfluidity and condensation in a 3D Bose gas after a quantum quench, revealing that superfluidity is more fragile than condensation and enabling dynamic Bose glass formation.

Contribution

It demonstrates that disorder can more strongly suppress superfluidity than condensation in a nonequilibrium 3D Bose gas, suggesting a method to engineer Bose Glass dynamically.

Findings

Disorder destroys superfluidity more than condensate in nonequilibrium.

Normal fluid density exceeds 4/3 of condensate depletion after quench.

Potential for experimental observation of dynamic Bose Glass formation.

Abstract

In an equilibrium three-dimensional (3D) disordered condensate, it's well established that disorder can generate an amount of normal fluid equaling to $\frac{4}{3}$ of the condensate depletion. The concept that the superfluid is more volatile to the existence of disorder than the condensate is crucial to the understanding of Bose glass phase. In this Letter, we show that, by bringing a weakly disordered 3D condensate to nonequilibrium regime via a quantum quench in the interaction, disorder can destroy superfluid significantly more, leading to a steady state in which the normal fluid density far exceeds $\frac{4}{3}$ of the condensate depletion. This suggests a possibility of engineering Bose Glass in the dynamic regime. As both the condensate density and superfluid density are measurable quantities, our results allow an experimental demonstration of the dramatized interplay between the disorder and interaction in the nonequilibrium scenario.