Josephson frequency of resonantly-coupled atomic and molecular condensates

TL;DR

This paper investigates the magnetic-field dependence of the Josephson frequency in atom-molecule condensates near a Feshbach resonance, incorporating many-body effects and effective range parameters to match experimental observations.

Contribution

It introduces a comprehensive model including many-body effects and effective range corrections to accurately predict Josephson frequencies near Feshbach resonances.

Findings

Excellent agreement with experimental data across magnetic field range

Effective range parameter is crucial for accurate frequency predictions

Many-body shifts significantly influence the Josephson frequency near resonance

Abstract

Motivated by recent experiments [Claussen N R et al. 2003 Preprint cond-mat/0302195] we investigate the magnetic-field dependence of the Josephson frequency of coherent atom-molecule oscillations near a Feshbach resonance. Far off resonance this frequency is determined by two-body physics. However, the Josephson frequency is relatively large and a description purely in terms of scattering lengths turns out to be inadequate. In particular, we have to include the effective range parameter of the interatomic interaction in our calculations. Close to resonance, the frequency deviates from the two-body results due to various many-body shifts. Considering also the many-body effects, we find perfect agreement with the experimental results over the entire range of magnetic field.