Feshbach-resonant Raman photoassociation in a Bose-Einstein condensate

TL;DR

This paper models the process of forming heteronuclear molecules in a Bose-Einstein condensate using Feshbach-resonant Raman photoassociation, highlighting the effects of pulse sequencing and collision strengths on efficiency.

Contribution

It introduces a detailed model for Feshbach-resonant Raman photoassociation in BECs, analyzing pulse sequences and collision effects on molecule formation efficiency.

Findings

Weak Raman photoassociation is significantly enhanced by pulse sequencing.

Strong intra-atom and molecule collisions decrease efficiency.

Inter-atom collisions unexpectedly increase molecule production efficiency.

Abstract

We model the formation of stable heteronuclear molecules via pulsed Raman photoassociation of a two-component Bose-Einstein condensate near a strong Feshbach resonance, for both counterintuitive and intuitive pulse sequencing. Compared to lasers alone, weak Raman photoassociation is enhanced by as much as a factor of ten (five) for a counterintuitive (intuitive) pulse sequence, whereas strong Raman photoassociation is barely enhanced at all--regardless of pulse sequence. Stronger intra-atom, molecule, or atom-molecule collisions lead to an expected decrease in conversion efficiency, but stronger ambient inter-atom collisions lead to an unexpected increase in the efficiency of stable molecule production. Numerical results agree reasonably with an analytical approximation.