Pulsed Adiabatic Photoassociation via Scattering Resonances

TL;DR

This paper develops a theoretical framework for pulsed adiabatic photoassociation of ultracold atoms, demonstrating how scattering resonances can significantly enhance the formation of ultracold molecules, with potential experimental applications.

Contribution

The authors introduce a novel computational method replacing the continuum with effective modes to analyze ARPA in the presence of scattering resonances, showing its effectiveness in molecule formation.

Findings

Resonances greatly aid in forming deeply bound molecules.

Single-event transfer yield approaches unity for wide resonances.

Ensemble-averaged transfer yield is higher for narrow resonances.

Abstract

We develop the theory for the Adiabatic Raman Photoassociation (ARPA) of ultracold atoms to form ultracold molecules in the presence of scattering resonances. Based on a computational method in which we replace the continuum with a discrete set of "effective modes", we show that the existence of resonances greatly aids in the formation of deeply bound molecular states. We illustrate our general theory by computationally studying the formation of $^{85}$Rb$_2$ molecules from pairs of colliding ultracold $^{85}$Rb atoms. The single-event transfer yield is shown to have a near-unity value for wide resonances, while the ensemble-averaged transfer yield is shown to be higher for narrow resonances. The ARPA yields are compared with that of (the experimentally measured) "Feshbach molecule" magneto-association. Our findings suggest that an experimental investigation of ARPA at sub-$\mu$K temperatures is warranted.