Observation of a disordered bosonic insulator from weak to strong interactions

TL;DR

This study uses ultracold atoms to explore disordered bosonic systems across different interaction strengths, revealing an insulating phase that persists from weak to strong interactions and identifying a coexistence of Bose glass and Mott insulator phases.

Contribution

It provides comprehensive experimental evidence of the disordered bosonic insulator phase across the full interaction range, including the coexistence of Bose glass and Mott insulator states.

Findings

Evidence of an insulating regime from weak to strong interactions

Identification of a Bose glass coexisting with a Mott insulator at strong interactions

Agreement with theoretical predictions for disordered bosonic systems

Abstract

We employ ultracold atoms with controllable disorder and interaction to study the paradigmatic problem of disordered bosons in the full disorder-interaction plane. Combining measurements of coherence, transport and excitation spectra, we get evidence of an insulating regime extending from weak to strong interaction and surrounding a superfluid-like regime, in general agreement with the theory. For strong interaction, we reveal the presence of a strongly-correlated Bose glass coexisting with a Mott insulator.