Many-Body Effects on Nonadiabatic Feshbach Conversion in Bosonic Systems

TL;DR

This paper models how many-body effects influence the efficiency of converting cold bosonic atoms into molecules during Feshbach resonance sweeps, revealing deviations from traditional two-body Landau-Zener predictions.

Contribution

It introduces a quantum microscopic model that incorporates many-body effects, providing analytic expressions for molecular conversion efficiency and extending predictions to heteronuclear molecules.

Findings

Many-body effects significantly alter molecular production predictions.

Derived an analytic formula explaining experimental discrepancies.

Extended the model to heteronuclear molecule formation.

Abstract

We investigate the dynamics of converting cold bosonic atoms to molecules when an external magnetic field is swept across a Feshbach resonance. Our analysis relies on a zero temperature quantum microscopic model that accounts for many-body effects, triggering the association process. We show that the picture of two-body molecular production depicted by Landau-Zener model is significantly altered due to many-body effects. In nonadiabatic regime, we derive an analytic expression for molecular conversion efficiency that explains the discrepancy between the prediction of Landau-Zener formula and experimental data[Hodby et al., Phys. Rev. Lett. {\bf 94}, 120402 (2005)]. Our theory is further extended to the formation of heteronuclear diatomic molecules and gives some interesting predictions.