Disordered one-dimensional Bose-Fermi mixtures: The Bose-Fermi glass

TL;DR

This paper investigates a 1D disordered Bose-Fermi mixture, revealing a phase diagram with superfluid and glassy phases, including a novel Bose-Fermi glass, and proposes experimental methods to distinguish these phases.

Contribution

It provides the first complete phase diagram for disordered 1D Bose-Fermi mixtures, identifying a new coupled Bose-Fermi glass phase and analyzing its experimental signatures.

Findings

Identification of multiple phase transitions between superfluid and glassy states.

Discovery of a new Bose-Fermi glass phase where both species are localized.

Proposal of Bragg scattering as a method to distinguish localized phases.

Abstract

We analyze an interacting Bose-Fermi mixture in a 1D disordered potential using a combination of renormalization group and variational methods. We obtain the complete phase diagram in the incommensurate case as a function of bosonic and inter-species interaction strengths, in the weak disorder limit. We find that the system is characterized by several phase transitions between superfluid and various glassy insulating states, including a new Bose-Fermi glass phase, where both species are coupled and localized. We show that the dynamical structure factor, as measured through Bragg scattering experiments, can distinguish between the various localized phases and probe their dynamics.