Disordered bosons in one dimension: from weak to strong randomness criticality

TL;DR

This paper studies the superfluid-insulator transition in one-dimensional disordered bosons, revealing a change from universal to disorder-dependent critical behavior as disorder strength increases, supported by large-scale Monte Carlo simulations.

Contribution

It provides the first large-scale numerical analysis of the transition across different disorder regimes, confirming and extending theoretical predictions.

Findings

Weak disorder transition matches the clean system universality class.

Strong disorder leads to nonuniversal, disorder-dependent critical behavior.

Results align with recent perturbative and strong-disorder renormalization group theories.

Abstract

We investigate the superfluid-insulator quantum phase transition of one-dimensional bosons with off-diagonal disorder by means of large-scale Monte-Carlo simulations. For weak disorder, we find the transition to be in the same universality class as the superfluid-Mott insulator transition of the clean system. The nature of the transition changes for stronger disorder. Beyond a critical disorder strength, we find nonuniversal, disorder-dependent critical behavior. We compare our results to recent perturbative and strong-disorder renormalization group predictions. We also discuss experimental implications as well as extensions of our results to other systems.