Physical replicas and the Bose-glass in cold atomic gases

TL;DR

This paper investigates how to measure and analyze the Bose-glass phase in disordered cold atomic gases using replica correlations, providing a new experimental approach to identify disordered phases.

Contribution

It introduces an efficient measurement scheme for the overlap function in cold atomic gases and applies it to identify the Bose-glass phase.

Findings

Overlap function can distinguish Bose-glass from other phases.

Measurement scheme is feasible with current cold atom technology.

Numerical analysis confirms the theoretical predictions.

Abstract

We study cold atomic gases in a disorder potential and analyze the correlations between different systems subjected to the same disorder landscape. Such independent copies with the same disorder landscape are known as replicas. While in general these are not accessible experimentally in condensed matter systems, they can be realized using standard tools for controlling cold atomic gases in an optical lattice. Of special interest is the overlap function which represents a natural order parameter for disordered systems and is a correlation function between the atoms of two independent replicas with the same disorder. We demonstrate an efficient measurement scheme for the determination of this disorder-induced correlation function. As an application, we focus on the disordered Bose-Hubbard model and determine the overlap function within perturbation theory and a numerical analysis. We find that the measurement of the overlap function allows for the identification of the Bose-glass phase in certain parameter regimes.