Finite temperature phase diagram of a polarized Fermi gas in an optical lattice

TL;DR

This paper maps the phase diagram of a polarized Fermi gas in an optical lattice at finite temperatures, identifying regions of FFLO, Sarma, BCS, and normal phases, with experimental signatures discussed.

Contribution

It provides the first comprehensive phase diagrams considering temperature, polarization, and filling factor, highlighting the stability of FFLO phases in optical lattices.

Findings

FFLO phase appears in a significant part of the phase diagram.

Two critical points of different nature are identified.

Distinct momentum distribution signatures for each phase are proposed.

Abstract

We present phase diagrams for a polarized Fermi gas in an optical lattice as a function of temperature, polarization, and lattice filling factor. We consider the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO), Sarma or breached pair (BP), and BCS phases, and the normal state and phase separation. We show that the FFLO phase appears in a considerable portion of the phase diagram. The diagrams have two critical points of different nature. We show how various phases leave clear signatures to momentum distributions of the atoms which can be observed after time of flight expansion.