Two-channel model of photoassociation in the vicinity of a Feshbach resonance

TL;DR

This paper develops a two-channel model to accurately describe photoassociation near a Feshbach resonance, simplifying complex multi-channel calculations into a minimal parameter framework, and corrects previous results for better predictive power.

Contribution

The paper introduces a corrected two-channel model that captures photoassociation near Feshbach resonances with only a few parameters, improving upon previous approximations.

Findings

Two parameters fully describe the PA process.

The model reproduces multi-channel results with high accuracy.

Resonance enhancement relates to the vanishing transition rate point.

Abstract

We derive the two-channel (TC) description of the photoassociation (PA) process in the presence of a magnetic Feshbach resonance and compare to full coupled multi-channel calculations for the scattering of $^{6}$Li-$^{87}$Rb. Previously derived results [P. Pellegrini et al., Phys. Rev. Lett. 101, 053201 (2008)] are corrected. The PA process is shown to be fully described by two parameters: the maximal transition rate and the point of vanishing transition rate. The TC approximation reproduces excellently the PA transition rates of the full multi-channel calculation and reveals, e.g., that the enhancement of the rate at a resonance is directly connected to the position of vanishing rate. For the description of two independent resonances it was found that only three parameters completely characterize the PA process.