Finite temperature disordered bosons in two dimensions

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.

Article (5 pages, 1 figure) and Supplemental Material (6 pages, 9 figures). v2: updated abstract, references, typos, plus small changes in text and supplemental material. v3: published version