Quasi-one-dimensional polarized Fermi superfluids

TL;DR

This paper explores the phase diagram of polarized Fermi gases in quasi-one-dimensional optical lattices, highlighting the stabilization of the FFLO superfluid phase due to dimensional crossover effects.

Contribution

It provides a detailed analysis of the zero-temperature phase diagram showing how weak inter-tube tunneling stabilizes the FFLO phase in quasi-1D systems.

Findings

FFLO phase is stabilized in the quasi-1D regime.

A phase transition from gapless to gapped quasiparticle spectrum occurs.

Dimensional crossover influences the superfluid properties.

Abstract

We calculate the zero temperature phase diagram of a polarized two-component Fermi gas in an array of weakly-coupled parallel one-dimensional (1D) 'tubes' produced by a two-dimensional optical lattice. Increasing the lattice strength drives a crossover from three-dimensional (3D) to 1D behavior, stabilizing the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) modulated superfluid phase. We argue that the most promising regime for observing the FFLO phase is in the quasi-1D regime, where the atomic motion is largely 1D but there is weak tunneling in the other directions that stabilizes long range order. In the FFLO phase, we describe a phase transition where the quasiparticle spectrum changes from gapless near the 3D regime to gapped in quasi-1D.