Cross-Species Interactions in the ⁸⁷Rb-⁴⁰K Bose-Fermi Mixture

Jon Goldwin

JILA, University of Colorado, UCB 0440, USA

Dilute gas Bose-Fermi mixtures offer unique and flexible model systems for studies of quantum mechanical many-body ensembles. Knowledge of the cross-species scattering length aBF is essential in determining the static and dynamic properties of such mixtures. We have used cross-dimensional rethermalization to measure the magnitude of aBF. In these measurements we have introduced a technique that eliminates the large systematic uncertainty in atom number, leading to a high precision determination of aBF. Furthermore we have recently observed for the first time a number of inter-species Feshbach resonances. These measurements refine our knowledge of the background scattering properties of the system, while making possible a wide range of new experiments relying on the unique tunability of the interactions that can now be achieved.