Ultracold collisions in chromium: D-wave Feshbach resonance and rf-assisted molecule association

We create Bose-Einstein Condensates of 52Cr atoms using an all-optical procedure [1]. In this contribution, we present the methods that we have developed to combat strong inelastic collisions in a Cr-MOT and reach degeneracy. We use intense and rapid rf sweeps to time-average to zero the magnetic trapping potential experienced by metastable dark states. This allows for the capture of all the magnetic sublevels of the metastable atoms in an optical trap superimposed to the MOT and it induces a reduction of inelastic losses in the mixed “optical+magnetic” trap used prior to the evaporation stage [2].