Simple Mean-Field Theory for a Zero-Temperature Fermi Gas at a Feshbach Resonance

TL;DR

This paper introduces a straightforward mean-field model for a zero-temperature Fermi gas near a Feshbach resonance, aligning well with experimental data and emphasizing the non-universality due to molecular structure.

Contribution

It provides a simple two-channel mean field theory that accurately describes the behavior of a Fermi gas near a Feshbach resonance, matching recent experimental observations.

Findings

Model agrees with experimental measurements of molecule fraction

Results highlight the importance of molecular structure in non-universal behavior

Applicable to strongly-coupled Li-6 Fermi gases

Abstract

We present a simple two-channel mean field theory for a zero-temperature two-component Fermi gas in the neighborhood of a Feshbach resonance. Our results agree with recent experiments on the bare-molecule fraction as a function of magnetic field [Partridge et al., cond-mat/0505353]. Even in this strongly-coupled gas of Li-6, the experimental results depend on the structure of the molecules formed in the Feshbach resonance and, therefore, are not universal.