Efimov physics in an ultracold Bose-Fermi mixture with large mass imbalance

An ultracold Bose-Fermi mixture of Cs and Li atoms constitutes a prototypical system with large mass imbalance that allows the exploration of many intriguing phenomena in few- and many-body physics. One of such is the heteronuclear Efimov effect, due to which an infinite geometrical series of bound three-body states can be formed, given that the two-body interactions are resonant. Here we present the recent observations of consecutive Efimov resonances through measurements of three-body loss coefficients near the broad Feshbach resonance.\footnote{R. Pires {\emph et al.}, PRL 112, 250404 (2014); PRA 90, 012710 (2014). See also: S.-K. Tung \emph{et al.}, PRL 113, 240402 (2014).} A refined analysis of the Feshbach resonance\footnote{J. Ulmanis {\emph et al.}, arXiv:1501.04799.} allows us to obtain an improved determination of the scaling of the Efimov resonances, which slightly deviates from the predicted universal scaling factor for the LiCs system. In a recent study, we have determined the effect of the Cs-Cs scattering length on the three-body parameter of the Efimov resonances.