Interband physics in an ultra-cold Fermi gas in an optical lattice

TL;DR

This paper investigates the complex phase behavior of strongly polarized ultracold fermions in optical lattices with populated p-bands, revealing potential magnetic and paired phases depending on interaction types.

Contribution

It derives a Hamiltonian for p-band populated fermions and predicts novel magnetic and pairing phases in this system.

Findings

Checkerboard anti-ferromagnetic order possible with repulsive interactions.

Transitions between different paired phases for attractive interactions.

Provides a theoretical framework for p-band physics in cold atom systems.

Abstract

We study a gas of strongly polarized cold fermions in an optical lattice when the excited p-bands are populated. We derive the relevant Hamiltonian and discuss the expected phase diagram for both repulsive and attractive interactions. In the parameter regime covered here, checkerboard anti-ferromagnetic ordering is found to be possible for repulsive interactions while for attractive interactions, transitions between different types of paired phases are predicted.