Orbital order of spinless fermions near an optical Feshbach resonance

TL;DR

This paper investigates the quantum phases of a three-color Hubbard model for spinless fermions in optical lattices, revealing novel orbital order phases induced by optical Feshbach resonances.

Contribution

It derives the orbital exchange constants from microscopic scattering and predicts new axial orbital order phases in the phase diagram.

Findings

Identification of axial orbital order phases

Derivation of orbital exchange constants from scattering data

Prediction of novel orbital arrangements in optical lattices

Abstract

We study the quantum phases of a three-color Hubbard model that arises in the dynamics of the p-band orbitals of spinless fermions in an optical lattice. Strong, color-dependent interactions are induced by an optical Feshbach resonance. Starting from the microscopic scattering properties of ultracold atoms, we derive the orbital exchange constants at 1/3 filling on the cubic optical lattice. Using this, we compute the phase diagram in a Gutzwiller ansatz. We find novel phases with 'axial orbital order' in which pz and px + ipy (or px - ipy) orbitals alternate.