Bosons in Disordered Optical Potentials

TL;DR

This paper systematically studies how different types and strengths of disorder affect the condensate, superfluidity, and phase transitions in interacting Bose gases in optical potentials, revealing the presence of a normal condensate component in the Bose glass phase.

Contribution

It provides a comprehensive numerical analysis of the effects of various disorder types on Bose gases, highlighting the coexistence of normal condensate components in the Bose glass phase.

Findings

Bose glass contains a normal condensate component.

Disorder type and strength significantly influence condensate properties.

Superfluidity and phase transitions are affected by disorder characteristics.

Abstract

In this work we systematically investigate the condensate properties, superfluid properties and quantum phase transitions in interacting Bose gases trapped in disordered optical potentials. We numerically solve the Bose-Hubbard Hamiltonian exactly for different: (a) types of disorder, (b) disorder strengths, and (c) interatomic interactions. The three types of disorder studied are: quasiperiodic disorder, uniform random disorder and random speckle-type disorder. We find that the Bose glass, as identified by Fisher et al [Phys. Rev. B {\bf 40}, 546 (1989)], contains a normal condensate component and we show how the three different factors listed above affect it.