Heteronuclear Molecules in a 3D Optical Lattice

Andreas Schindewolf, Lukas Reichs ollner, Hanns-Christoph N agerl +2 more

Bo Yan

Jacob P. Covey

Xiao Li, Ted Corcovilos, Yang Wang +2 more

C. Ospelkaus, Silke Ospelkaus, Leif Humbert +3 more

We report on the creation of ultracold heteronuclear molecules assembled from fermionic 40K and bosonic 87Rb atoms in a 3D optical lattice. Molecules are produced at a heteronuclear Feshbach resonance on both the attractive and the repulsive sides of the resonance. We precisely determine the binding energy of the heteronuclear molecules from rf spectroscopy across the Feshbach resonance. We characterize the lifetime of the molecular sample as a function of magnetic field and measure lifetimes between 20 and 120 ms. The efficiency of molecule creation via rf association is measured and is found to decrease as expected for more deeply bound molecules.

C. Ospelkaus, S Ospelkaus

This PhD tutorial article is a review of our experiments on heteronuclear quantum gas mixtures at the University of Hamburg. We introduce basic properties of trapped Fermi-Bose mixtures and demonstrate the achievement of large quantum degenerate mixtures of 40K and 87Rb. Using heteronuclear Feshbach resonances, we show how the heteronuclear interaction can be tuned, allowing us to induce phase separation and collapse for large repulsive and attractive interactions, respectively. We realize Fermi-Bose mixtures in 3D optical lattices as a novel quantum many-body system and study coherence properties of the mixture. Combining our experiments on lattices and Feshbach resonances, we present the first realization of ultracold heteronuclear Feshbach molecules. The molecules are created at individual sites of a 3D optical lattice. We discuss lifetime, binding energy and rf association efficiency in terms of a universal model and give an outlook for possible future developments.