Feshbach resonances in an optical lattice

TL;DR

This paper develops a theoretical framework for ultracold atomic gases in optical lattices near Feshbach resonances, incorporating atom-molecule interactions, tunneling, and phase diagram analysis.

Contribution

It introduces a generalized Hubbard model with microscopic parameters derived from experimental data, describing atom-molecule physics in optical lattices near Feshbach resonances.

Findings

Derived microscopic parameters for the Hubbard model.

Analyzed the zero-temperature phase diagram of Bose gases.

Described atom-molecule tunneling and avoided crossings.

Abstract

We present the theory for ultracold atomic gases in an optical lattice near a Feshbach resonance. In the single-band approximation the theory describes atoms and molecules which can both tunnel through the lattice. Moreover, an avoided crossing between the two-atom and the molecular states occurs at every site. We determine the microscopic parameters of the generalized Hubbard model that describes this physics, using the experimentally known parameters of the Feshbach resonance in the absence of the optical lattice. As an application we also calculate the zero-temperature phase diagram of an atomic Bose gas in an optical lattice.