Disordered ultracold atomic gases in optical lattices: A case study of Fermi-Bose mixtures

TL;DR

This review explores the properties and phases of ultracold Fermi-Bose mixtures in disordered optical lattices, highlighting the formation of composite fermions and various quantum disordered states.

Contribution

It provides a comprehensive overview of quantum disordered phases in ultracold Fermi-Bose mixtures, emphasizing the role of disorder and interactions in these systems.

Findings

Identification of composite fermions as key quasiparticles

Discussion of various quantum disordered phases like Fermi glasses and spin glasses

Methods for detecting quantum disordered states in ultracold gases

Abstract

We present a review of properties of ultracold atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices. In the strong interacting limit and at very low temperatures, fermions form, together with bosons or bosonic holes, {\it composite fermions}. Composite fermions behave as a spinless interacting Fermi gas, and in the presence of local disorder they interact via random couplings and feel effective random local potential. This opens a wide variety of possibilities of realizing various kinds of ultracold quantum disordered systems. In this paper we review these possibilities, discuss the accessible quantum disordered phases, and methods for their detection. The discussed quantum phases include Fermi glasses, quantum spin glasses, "dirty" superfluids, disordered metallic phases, and phases involving quantum percolation.