Coherent molecular bound states of bosons and fermions near a Feshbach resonance

TL;DR

This paper presents an exact solution-based analysis of molecular bound states in atomic quantum gases near a Feshbach resonance, bridging BEC and BCS theories and aligning well with experimental data.

Contribution

It introduces a simple, renormalizable field theoretic model with exact two-body solutions that unify BEC and BCS regimes and serve as a variational framework for resonant superfluidity.

Findings

Exact solutions match experimental binding energies in bosonic and fermionic gases.

The model interpolates smoothly between BEC and BCS regimes.

Provides a versatile variational approach for superfluidity near Feshbach resonances.

Abstract

We analyze molecular bound states of atomic quantum gases near a Feshbach resonance. A simple, renormalizable field theoretic model is shown to have exact solutions in the two-body sector, whose binding energy agrees well with observed experimental results in both Bosonic and Fermionic cases. These solutions, which interpolate between BEC and BCS theories, also provide a more general variational ansatz for resonant superfluidity and related problems.