Bosons in a two-dimensional bichromatic quasiperiodic potential: Analysis of the disorder in the Bose-Hubbard parameters and phase diagrams

TL;DR

This paper investigates how disorder in the Bose-Hubbard parameters, caused by bichromatic quasiperiodic potentials, affects phase diagrams of bosons in optical lattices, revealing significant deviations from models with only on-site disorder.

Contribution

It provides a detailed analysis of the distribution of Bose-Hubbard parameters in bichromatic potentials and assesses their impact on phase diagrams using a local mean-field approach.

Findings

Significant disorder found in hopping strengths.

Disorder causes notable deviations in phase diagrams.

Hopping disorder impacts superfluid-insulator transitions.

Abstract

Experimental realizations of disorder in optical lattices generate a distribution of the Bose-Hubbard (BH) parameters, like on-site potentials, hopping strengths, and interaction energies. We analyze this distribution for bosons in a bichromatic quasi-periodic potential by determining the generalized Wannier functions and calculating the corresponding BH parameters. Using a local mean-field cluster analysis, we study the effect of the corresponding disorder on the phase diagrams. We find a substantial amount of disorder in the hopping strengths, which produces strong deviations from the phase diagram of the disordered BH model with solely random on-site potentials.