Many-Body Rate Limit on Photoassociation of a Bose-Einstein Condensate

TL;DR

This paper investigates the fundamental limits of atom-molecule conversion rates in a Bose-Einstein condensate during photoassociation, revealing a many-body rate limit influenced by spontaneous decay and density effects.

Contribution

It introduces an upgraded model including spontaneous decay, showing how it shifts the photoassociation resonance and affects the rate limit, with analytical and numerical validation.

Findings

Spontaneous decay causes a shift in the photoassociation resonance.

The many-body rate limit is more restrictive than the two-body unitary limit.

Analytical model agrees with experiments at high density.

Abstract

We briefly report on zero-temperature photoassociation of a Bose-Einstein condensate, focusing on the many-body rate limit for atom-molecule conversion. An upgraded model that explicitly includes spontaneous radiative decay leads to an unanticipated shift in the position of the photoassociation resonance, which affects whether the rate (constant) maximizes or saturates, as well as the limiting value itself. A simple analytical model agrees with numerical experiments, but only for high density. Finally, an explicit comparison with the two-body unitary limit, set by the size of the condensate, finds that the many-body rate limit is generally more strict.