Spatial separation in a thermal mixture of ultracold174Yb and 87Rb atoms
F. Baumer, F. Munchow, A. Gorlitz, Stephen E. Maxwell, Paul S. Julienne, Eite Tiesinga
We report on the observation of unusually strong interactions in a thermal mixture of ultracold atoms which cause a significant modification of the spatial distribution. A mixture of 87Rb and 174Yb with a temperature of a few μK is prepared in a hybrid trap consisting of a bichromatic optical potential superimposed on a magnetic trap. For suitable trap parameters and temperatures, a spatial separation of the two species is observed. We infer that the separation is driven by a large interaction strength between 174Yb and 87Rb and a correspondingly large three-body recombination rate. A diffusion model of the spatial separation supports this conclusion.