Quantifying the nonuniversal three-body losses in ultracold atomic gases has been a long-standing problem. We go beyond earlier approaches to solve this problem by using a model that includes realistic pairwise interaction potentials and the exact three-atom spin structure. With this model we can successfully explain experimental observations for weakly interacting ${}^7\mathrm{Li}$ and ${}^{87}\mathrm{Rb}$ atoms. Capturing the exact spin structure, we are able to reveal a strong three-body spin-exchange recombination mechanism. In addition, we predict a regime of low three-body recombination rate in the ${}^7\mathrm{Li}$ system that is advantageous for a variety of many-body experiments. This work opens avenues to study spin-involved few-body processes in quantum gases.

• Received 23 July 2021
• Accepted 9 February 2022

DOI:https://doi.org/10.1103/PhysRevResearch.4.023103

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society