Enhanced association and dissociation of heteronuclear Feshbach molecules in a microgravity environment

TL;DR

This paper explores the dynamics of heteronuclear Feshbach molecules in a microgravity environment, demonstrating high-efficiency association and dissociation with suppressed thermal and loss effects, and providing a theoretical model for optimal experimental conditions.

Contribution

It introduces a theoretical framework for heteronuclear molecule dynamics in microgravity, highlighting conditions for high efficiency and coherence in atom-molecule transitions.

Findings

High efficiency in molecule association and dissociation in microgravity.

Suppressed thermal and loss effects enable coherence in transitions.

Derived optimal temperature, density, and scattering length regimes for experiments.

Abstract

We study the association and dissociation dynamics of weakly bound heteronuclear Feshbach molecules using transverse RF-fields for expected parameters accessible through the microgravity environment of NASA's Cold Atom Laboratory (CAL) aboard the International Space Station, including temperatures at or below nK and atomic densities as low as $10^8$/cm$^3$. We show that under such conditions, thermal and loss effects can be greatly suppressed resulting in high efficiency in both association and dissociation of Feshbach molecules with mean size exceeding 10$^4a_0$, and allowing for the coherence in atom-molecule transitions to be clearly observable. Our theoretical model for heteronuclear mixtures includes thermal, loss, and density effects in a simple and conceptually clear manner. We derive the temperature, density and scattering length regimes of $^{41}$K-$^{87}$Rb that allow optimal association/dissociation efficiency with minimal heating and loss to guide future experiments with ultracold atomic gases in space.