We study three-body recombination in an ultracold Bose-Fermi mixture. We first show theoretically that, for weak interspecies coupling, the loss rate is proportional to Tan’s contact. Second, using a 7Li/6Li 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 to nf4/3 where nf is the Fermi gas density.
This unusual exponent signals nontrivial two-body correlations in the system.
Our results demonstrate that few-body losses can be used as a quantitative probe of quantum correlations in many-body ensembles .
 Sébastien Laurent, Matthieu Pierce, Marion Delehaye, Tarik Yefsah, Frédéric Chevy, and Christophe Salomon, Phys. Rev. Lett., 118, 103403 (2017)