Atomic Bose-Fermi mixtures in an optical lattice

TL;DR

This paper explores the rich quantum phase diagram of ultracold Bose-Fermi mixtures in optical lattices, predicting novel phases like paired states and density waves, and discusses their experimental observability.

Contribution

It introduces a comprehensive analysis of phase behavior in Bose-Fermi mixtures, highlighting new quantum phases involving pairing and composite fermions under strong interactions.

Findings

Prediction of fermion-boson pairing phases

Identification of density wave and superfluid phases

Feasibility discussion for experimental observation

Abstract

A mixture of ultracold bosons and fermions placed in an optical lattice constitutes a novel kind of quantum gas, and leads to phenomena, which so far have been discussed neither in atomic physics, nor in condensed matter physics. We discuss the phase diagram at low temperatures, and in the limit of strong atom-atom interactions, and predict the existence of quantum phases that involve pairing of fermions with one or more bosons, or, respectively, bosonic holes. The resulting composite fermions may form, depending on the system parameters, a normal Fermi liquid, a density wave, a superfluid liquid, or an insulator with fermionic domains. We discuss the feasibility for observing such phases in current experiments.