Atom-molecule theory of broad Feshbach resonances

TL;DR

This paper develops an atom-molecule theoretical framework for broad Feshbach resonances in atomic gases, accurately capturing two-atom physics and matching experimental magnetic moment measurements of ^{6}Li near 834 Gauss.

Contribution

It introduces a many-body atom-molecule theory that precisely incorporates two-atom physics for broad Feshbach resonances, improving understanding of experimental observations.

Findings

Accurately calculates the magnetic moment of ^{6}Li near the broad Feshbach resonance.

Shows excellent agreement with experimental measurements by Jochim et al.

Provides a theoretical basis for understanding atom-molecule interactions in broad resonances.

Abstract

We derive the atom-molecule theory for an atomic gas near a broad Feshbach resonance, where the energy dependence of the atom-molecule coupling becomes crucial for understanding experimental results. We show how our many-body theory incorporates the two-atom physics exactly. In particular, we calculate the magnetic moment of a two-component gas of ^{6}Li atoms for a wide range of magnetic fields near the broad Feshbach resonance at about 834 Gauss. We find excellent agreement with the experiment of Jochim et al. [Phys. Rev. Lett. 91, 240402 (2003)].