Spatial separation in a thermal mixture of ultracold {sup 174}Yb and {sup 87}Rb atoms

Abstract

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 {sup 87}Rb and {sup 174}Yb with a temperature of a few {mu}K 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 {sup 174}Yb and {sup 87}Rb accompanied by a large three-body recombination rate. Based on this assumption we have developed a diffusion model which reproduces our observations.