Quantum degenerate mixtures of Cs and Yb

We report the production of quantum degenerate Bose-Bose mixtures of Cs and Yb with both attractive (Cs + Yb-174) and repulsive (Cs + Yb-170) interspecies interactions. Dual-species evaporation is performed in a bichromatic optical dipole trap that combines light at 1070 nm and 532 nm to enable control of the relative trap depths for Cs and Yb. Maintaining a trap which is shallower for Yb throughout the evaporation leads to highly efficient sympathetic cooling of Cs for both isotopic combinations at magnetic fields close to the Efimov minimum in the Cs three-body recombination rate at around 22 G. For Cs + Yb-174, we produce quantum mixtures with typical atom numbers of N-Yb similar to 5 x 10(4) and N-Cs similar to 5 x 10(3). We find that the attractive interspecies interaction (characterized by the scattering length a(CsYb) = -75a(0)) is stabilized by the repulsive intraspecies interactions. For Cs + Y-170(b), we produce quantum mixtures with typical atom numbers of N-Yb similar to 4 x 10(4) and N-Cs similar to 1 x 10(4). Here, the repulsive interspecies interaction (a(CsYb) = 96a(0)) can overwhelm the intraspecies interactions, such that the mixture sits in a region of partial miscibility.

Automated summary

Production of quantum degenerate Bose-Bose mixtures of Cs and Yb with both attractive and repulsive interspecies interactions is reported. Dual-species evaporation in a bichromatic optical dipole trap allows for efficient sympathetic cooling of Cs. For Cs + Yb-174, the attractive interspecies interaction is stabilized by repulsive intraspecies interactions, while for Cs + Yb-170(b), the repulsive interspecies interaction can overwhelm the intraspecies interactions, resulting in partial miscibility of the mixture.