Heteronuclear Feshbach resonances in a mixture of ultracold $^{87}$Rb and $^{133}$Cs

We present the first observation of heteronuclear Feshbach resonances in a bosonic mixture of ultracold $^{133}$Cs and $^{87}$Rb. We give an overview of our experimental setup and the procedure of all-optical sample preparation. One of the key ingredients is the use of simultaneous degenerate Raman sideband cooling on both species. We perform Feshbach spectroscopy on a mixture of $\sim $10$^{6}$ atoms, optically trapped at a temperature of a few $\mu $K, by recording trap loss. We find a rich structure of interspecies Feshbach resonances within a magnetic field ranging from 0G to 300G. A consistent assignment of the observed Feshbach resonances will allow us to quantify the interspecies collisional properties. We discuss potential pathways towards obtaining a double-degenerate bosonic quantum gas and towards the production of ground state RbCs molecules.