Formation of molecules from a Cs Bose-Einstein condensate

TL;DR

This paper presents a theoretical model explaining the conversion of a Cs Bose-Einstein condensate into molecules, matching experimental results and predicting higher efficiencies under certain conditions.

Contribution

It provides a detailed theoretical description of molecule formation from a BEC, estimating resonance strength and deactivation rates, and analyzing sensitivity to experimental conditions.

Findings

Conversion efficiency of over 30% observed experimentally.

Theoretical estimates of resonance strength and deactivation rates.

Predicted 60% efficiency at lower densities and sweep rates.

Abstract

Conversion of an expanding Bose-Einstein condensate of Cs atoms to a molecular one with an efficiency of more than 30% was observed recently in experiments by M. Mark et al., Europhys. Lett. 69, 706 (2005). The theory presented here describes the experimental results. Values of resonance strength of 8 mG and rate coefficients for atom-molecule deactivation of $1\times 10^{-11}$ cm$^{3}/$s and molecule-molecule one of $1.5\times 10^{-9}$ cm$^{3}/$s are estimated by a fit of the theoretical results to the experimental data. Near the resonance, where the highest conversion efficiency was observed, the results demonstrate strong sensitivity to the magnetic field ripple and inhomogeneity. A conversion efficiency of about 60% is predicted by non-mean-field calculations for the densities and sweep rates lower than the ones used in the experiments.