Finite temperature disordered bosons in two dimensions

TL;DR

This paper investigates phase transitions of a weakly interacting 2D Bose gas in a random potential at finite temperatures, identifying different phases and constructing a phase diagram, highlighting the effects of trap barriers on localization.

Contribution

It provides a detailed phase diagram for 2D disordered Bose gases at finite temperature, including the effects of trap barriers on localization and phase coexistence.

Findings

Identifies superfluid, normal fluid, and insulator phases in 2D disordered Bose gases.

Constructs a phase diagram showing phase coexistence and transitions.

Shows that trap barriers limit localization length, maintaining insulator phase at all temperatures.

Abstract

We study phase transitions in a two dimensional weakly interacting Bose gas in a random potential at finite temperatures. We identify superfluid, normal fluid, and insulator phases and construct the phase diagram. At T=0 one has a tricritical point where the three phases coexist. The truncation of the energy distribution at the trap barrier, which is a generic phenomenon in cold atom systems, limits the growth of the localization length and in contrast to the thermodynamic limit the insulator phase is present at any temperature.