Strongly interacting isotopic Bose-Fermi mixture immersed in a Fermi sea

Abstract

We have created a triply quantum-degenerate mixture of bosonic K-41 and two fermionic species K-40 and Li-6. The boson is shown to be an efficient coolant for the two fermions, spurring hopes for the observation of fermionic superfluids with imbalanced masses. We observe multiple heteronuclear Feshbach resonances, in particular a wide s-wave resonance for the combination K-41-K-40, opening up studies of strongly interacting isotopic Bose-Fermi mixtures. For large imbalance in the local densities of different species, we enter the polaronic regime of dressed impurities immersed in a bosonic or fermionic bath.