Disordered solid to Bose-glass transition in Bose-Hubbard model with disorder and long-range interactions

TL;DR

This paper explores the phase diagram of disordered two-dimensional Bose-Hubbard models with long-range interactions, revealing a quantum phase transition between disordered solid and Bose-glass phases influenced by disorder strength and inter-site correlations.

Contribution

It provides a comprehensive analysis of how long-range interactions and disorder affect quantum phases, including the transition between disordered solid and Bose-glass phases, using multiple theoretical approaches.

Findings

Identification of a quantum phase transition between DS and BG phases at high disorder.

Demonstration of the impact of long-range interactions on phase stability.

Insights into inter-site correlations affecting phase boundaries.

Abstract

The introduction of disorder in Bose-Hubbard model gives rise to new glassy quantum phases, namely the Bose-glass (BG) and disordered solid (DS) phases. In this work, we present the rich phase diagram of interacting bosons in disordered two-dimensional optical lattice, modelled by the disordered Bose-Hubbard model. We systematically probe the effect of long-range interaction truncated to the nearest neighbors and next-nearest neighbors on the phase diagram. We investigate the zero-temperature ground-state quantum phases using the single-site Gutzwiller mean field (SGMF) theory. We also employ strong-coupling perturbative expansion to identify the nature of ground-state solid phases analytically. At sufficiently high disorder strength, we observe a quantum phase transition between the DS and BG phases. We have investigated this transition in greater detail using cluster Gutzwiller mean field theory to study the effect of inter-site correlations which is absent in the SGMF method. We have also studied this phase transition from the perspective of percolation theory.