Coherence and Collisions of Ultracold cesium Molecules

The creation of ultracold molecules from a Bose-Einstein condensate of atoms opens the door to a new class of experiments on coherent molecular quantum matter, the physical behvior of which is governed by quantum coherence and many-body interactions. It is also an essential step toward quantum manipulation of complex objects and a deeper understanding of the coherence properties of matter waves. We propose to study ultracold molecules formed in cesium Bose-Einstein condensates via Feshbach resonances, which permit a direct transformation of interacting atom pairs into molecules in a single rovibrational level. The cold molecules can be spatially separated from the atoms by an external magnetic field (Stern-Gerlach effect) and stored in an optical trap. The main goals of the proposal are the optimization of the molecule formation process, the understanding of their fundamental interaction properties, and the exploration of the matter-wave coherence of the molecular ensemble. The proposal combines the expertise on Feshbach resonances that the applicant has obtained from his previous experiments at Stanford University with the Bose-Einstein condensate of cesium that is available as a worlwide unique tool in the group of the co-applicant at Innsbruck University.