Connecting few-body inelastic decay to many-body correlations: a weakly coupled impurity in a resonant Fermi gas

TL;DR

This paper links three-body recombination rates in ultracold Bose-Fermi mixtures to many-body correlations, demonstrating that impurity-induced losses can serve as a quantitative probe of these correlations across different regimes.

Contribution

It establishes a theoretical and experimental connection between three-body loss rates and Tan's contact in a Bose-Fermi mixture, revealing new insights into many-body correlations.

Findings

Loss rate proportional to Tan's contact at weak coupling

Recombination rate matches model predictions across BEC-BCS crossover

At unitarity, loss rate scales with the 4/3 power of fermionic density

Abstract

We study three-body recombination in an ultracold Bose-Fermi mixture. We first show theoretically that, for weak inter-species coupling, the loss rate is proportional to Tan's contact. Second, using a 7 Li/ 6 Li mixture we probe the recombination rate in both the thermal and dual superfluid regimes. We find excellent agreement with our model in the BEC-BCS crossover. At unitarity where the fermion-fermion scattering length diverges, we show that the loss rate is proportional the 4/3 power of the fermionic density. Our results demonstrate that impurity-induced losses can be used as a quantitative probe of many-body correlations.