Induced interactions for ultracold Fermi gases in optical lattices

TL;DR

This paper studies how optical lattices influence superfluidity in ultracold Fermi gases, showing that lattice effects significantly suppress the order parameter and extend mean-field theory validity, with results aligning with quantum Monte Carlo simulations.

Contribution

It applies the Gorkov--Melik-Barkhudarov correction to analyze lattice effects on superfluidity, providing improved theoretical predictions for ultracold Fermi gases in optical lattices.

Findings

Lattice effects strongly suppress the superfluid order parameter.

GMB corrections agree with quantum Monte Carlo results.

Extension of mean-field theory validity to broader lattice systems.

Abstract

We investigate the effect of optical lattices on the BCS superfluidity by using the Gorkov--Melik-Barkhudarov (GMB) correction for a two-component Fermi gas. We find that the suppression of the order parameter is strongly enhanced by the lattice effects. The predictions made by the GMB corrections are in qualitative and, for the cases studied, quantitative agreement with previous quantum Monte Carlo results. We discuss how the GMB correction extends the validity of the mean-field theory to a wider range of tunable optical lattice systems in different dimensions.