Strongly correlated Fermi-Bose mixtures in disordered optical lattices

TL;DR

This paper theoretically explores the low-temperature behavior of strongly correlated boson-fermion mixtures in disordered optical lattices, revealing the formation of composite fermions and complex quantum phases such as Fermi glasses and spin glasses.

Contribution

It introduces a novel effective Hamiltonian for strongly correlated Fermi-Bose mixtures in disordered lattices, highlighting the formation of composite fermions and their quantum phase diagram.

Findings

Composite fermions form under specific conditions.

The phase diagram includes Fermi glasses, spin glasses, and quantum percolation regimes.

Parameters can be controlled via interactions and inhomogeneities.

Abstract

We investigate theoretically the low-temperature physics of a two-component ultracold mixture of bosons and fermions in disordered optical lattices. We focus on the strongly correlated regime. We show that, under specific conditions, composite fermions, made of one fermion plus one bosonic hole, form. The composite picture is used to derive an effective Hamiltonian whose parameters can be controlled via the boson-boson and the boson-fermion interactions, the tunneling terms and the inhomogeneities. We finally investigate the quantum phase diagram of the composite fermions and we show that it corresponds to the formation of Fermi glasses, spin glasses, and quantum percolation regimes.