Magnetic Control of the Interaction in Ultracold K-Rb Mixtures

We predict the presence of several magnetic Feshbach resonances in selected Zeeman sublevels of the isotopic pairs ⁴⁰K-⁸⁷Rb and ⁴¹K-⁸⁷Rb at magnetic fields up to 10³   G. Positions and widths are determined combining a new measurement of the ⁴⁰K-⁸⁷Rb inelastic cross section with recent experimental results on both isotopes. The possibility of driving a K-Rb mixture from the weak to the strong interacting regime tuning the applied field should allow one to achieve the optimal conditions for boson-induced Cooper pairing in a multicomponent ⁴⁰K-⁸⁷Rb atomic gas and for the production of ultracold polar molecules.