Universal Superfluid Transition and Transport Properties of Two-Dimensional Dirty Bosons

TL;DR

This paper investigates the robustness of superfluidity in two-dimensional disordered bosonic systems and explores their transport properties, revealing a protected superfluid transition and evidence for a Bose bad-metal phase.

Contribution

It demonstrates that the superfluid transition remains of the BKT type under strong disorder and identifies a thermally activated conductance behavior indicating a Bose bad-metal phase.

Findings

Superfluid transition persists up to disorder strengths comparable to the chemical potential.

Conductance shows thermally activated behavior vanishing only at zero temperature.

Evidence for a Bose bad-metal phase as a precursor to the Bose-glass phase.

Abstract

We study the phase diagram of two-dimensional, interacting bosons in the presence of a correlated disorder in continuous space, using large-scale finite temperature quantum Monte Carlo simulations. We show that the superfluid transition is strongly protected against disorder. It remains of the Berezinskii-Kosterlitz-Thouless type up to disorder strengths comparable to the chemical potential. Moreover, we study the transport properties in the strong disorder regime where a zero-temperature Bose-glass phase is expected. We show that the conductance exhibits a thermally activated behavior vanishing only at zero temperature. Our results point towards the existence of Bose bad-metal phase as a precursor of the Bose-glass phase.