Order via Nonlinearity in Randomly Confined Bose Gases

TL;DR

This paper develops a mean-field theory for weakly interacting Bose gases in disordered potentials, revealing a transition from a normal gas to a localized Bose-glass phase and a subsequent transition to superfluidity.

Contribution

It introduces a novel mean-field framework to describe phase transitions in disordered Bose gases, including localization and superfluidity.

Findings

Normal gas to Bose-glass transition with localized excitations

First-order transition from Bose-glass to superfluid phase

Coexistence of phases at intermediate densities

Abstract

A Hartree-Fock mean-field theory of a weakly interacting Bose-gas in a quenched white noise disorder potential is presented. A direct continuous transition from the normal gas to a localized Bose-glass phase is found which has localized short-lived excitations with a gapless density of states and vanishing superfluid density. The critical temperature of this transition is as for an ideal gas undergoing Bose-Einstein condensation. Increasing the particle-number density a first-order transition from the localized state to a superfluid phase perturbed by disorder is found. At intermediate number densities both phases can coexist.