Three-body recombination rates near a Feshbach resonance within a two-channel contact interaction model

TL;DR

This paper models three-body recombination rates near a Feshbach resonance using a two-channel contact interaction, successfully matching experimental data and highlighting the impact of finite effective range.

Contribution

It introduces a two-channel contact interaction model that accurately describes three-body recombination near Feshbach resonances, including finite effective range effects.

Findings

The model quantitatively matches experimental recombination data.

Finite effective range reduces the universal scaling factor.

Narrower resonances exhibit larger deviations from universality.

Abstract

We calculate the three-body recombination rate into a shallow dimer in a gas of cold bosonic atoms near a Feshbach resonance using a two-channel contact interaction model. The two-channel model naturally describes the variation of the scattering length through the Feshbach resonance and has a finite effective range. We confront the theory with the available experimental data and show that the two-channel model is able to quantitatively describe the existing data. The finite effective range leads to a reduction of the scaling factor between the recombination minima from the universal value of 22.7. The reduction is larger for larger effective ranges or, correspondingly, for narrower Feshbach resonances.