Bose Condensed Gas in Strong Disorder Potential With Arbitrary Correlation Length

TL;DR

This paper investigates the effects of strong, correlated disorder on a dilute Bose condensate at zero temperature, revealing a first-order phase transition where superfluidity vanishes, extending previous models to stronger disorder regimes.

Contribution

It generalizes the Huang and Meng model to include strong disorder with arbitrary correlation length, providing a new integral equation for density and identifying the critical disorder strength for superfluidity loss.

Findings

Superfluid phase disappears via a first-order transition at a critical disorder strength.

Critical disorder strength depends on the correlation length of the disorder.

The model extends understanding of Bose gases in strong, correlated disorder environments.

Abstract

We study the properties of a dilute Bose condensed gas at zero temperature in the presence of a strong random potential with arbitrary correlation length. Starting from the underlying Gross-Pitaevskii equation, we use the random phase approximation in order to get a closed integral equation for the averaged density distribution which allows to determine both the condensate and the superfluid density. The obtained results generalize those of Huang and Meng (HM) to strong disorder. In particular, we find the critical value of the disorder strength, where the superfluid phase disappears by a first-order phase transition. We show how this critical value changes as a function of the correlation length.