Percolation analysis of a disordered spinor Bose gas

TL;DR

This paper investigates how disorder affects a spinor Bose gas in an optical lattice, identifying phase transitions among superfluid, Mott insulator, and Bose glass phases using percolation analysis.

Contribution

It introduces a percolation-based method to accurately distinguish phases in a disordered spinor Bose-Hubbard model, providing detailed phase diagrams for different spin interactions.

Findings

Bose glass phase appears with disorder in spinor Bose gases.

Percolation analysis effectively differentiates SF, MI, and BG phases.

Phase diagrams are constructed for both ferromagnetic and antiferromagnetic interactions.

Abstract

We study the effects of an on-site disorder potential in a gas of spinor (spin-1) ultracold atoms loaded in an optical lattice corresponding to both ferromagnetic and antiferromagnetic spin dependent interactions. Starting with a disordered spinor Bose-Hubbard model (SBHM) on a two dimensional square lattice, we observe the appearance of a Bose glass phase using the fraction of the lattice sites having finite superfluid order parameter and non integer local densities as an indicator. A precise distinction between three different types of phases namely, superfluid (SF), Mott insulator (MI) and Bose glass (BG) is done via a percolation analysis thereby demonstrating that a reliable enumeration of phases is possible at particular values of the parameters of the SBHM. Finally we present the phase diagram based on the above information for both antiferromagnetic and ferromagnetic interactions.