Feshbach resonances in an ultracold mixture of ⁸⁷Rb and ⁴⁰K

We report the experimental preparations of the absolute ground states of ⁸⁷Rb and ⁴⁰K atoms (|F=1, m_F=1,〉+ |F=9/2, m_F=-9/2〉) by means of the radio-frequency and microwave adiabatic rapid passages, and the observation of magnetic Feshbach resonances in an ultracold mixture of bosonic ⁸⁷Rb and fermionic ⁴⁰K atoms between 0 T and 6.0 × 10^-2 T, including 7 homonuclear and 4 heteronuclear Feshbach resonances. The resonances are identified by the abrupt trap loss of atoms induced by the strong inelastic three-body collisions. These Feshbach resonances should enable the experimental control of interspecies interactions.