Emergence of a superglass phase in the random hopping Bose-Hubbard model

TL;DR

This paper investigates a quantum model of strongly correlated bosons with random hopping, revealing a superglass phase characterized by simultaneous glassy and superfluid orderings, using advanced analytical methods.

Contribution

It introduces the superglass phase in the infinite-range Bose-Hubbard model with random hopping, combining replica and Trotter-Suzuki techniques for analysis.

Findings

Identification of a superglass phase at the interface of glass and superfluid phases

Presence of competing glassy and superfluid order parameters

Phase diagrams illustrating the emergence of superglass in parameter space

Abstract

We study an experimentally feasible system of strongly correlated bosons with random hoppings, described by the infinite-range Bose-Hubbard model on a lattice with hopping integrals given by independent random variables of Gaussian distribution with non-zero mean. We solve this quantum model in the thermodynamic limit, employing the replica method and the Trotter-Suzuki formula. We find and describe a superglass phase that emerges at the interface between glass and superfluid phases. Both glassy and long-range orderings are present in the superglass and compete with each other, as revealed by the anticorrelation of their order parameters. We present phase diagrams in various cross-sections of the multidimensional space of system parameters. In selected parameter subspaces, we compare the results to those of non-disordered, diagonally-disordered, and once celebrated spin-glass systems.