Fragmentation and the Bose-glass phase transition of the disordered 1D Bose gas

TL;DR

This paper studies the superfluid-insulator quantum phase transition in a disordered 1D Bose gas using the probability distribution of density, providing an analytical criterion for phase detection applicable in experiments.

Contribution

It introduces a fragmentation criterion based on density distribution to identify the phase transition, supported by analytical derivation and numerical validation.

Findings

Superfluid phase has zero probability of zero density.

Insulator phase shows a nonzero probability of zero density.

The criterion effectively detects phase transition in trapped gases.

Abstract

We investigate the superfluid-insulator quantum phase transition in a disordered 1D Bose gas in the mean field limit, by studying the probability distribution of the density. The superfluid phase is characterized by a vanishing probability to have zero density, whereas a nonzero probability marks the insulator phase. This relation is derived analytically, and confirmed by a numerical study. This fragmentation criterion is particularly suited for detecting the phase transition in experiments. When a harmonic trap is included, the transition to the insulating phase can be extracted from the statistics of the local density distribution.