Hamburg 2009 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 6: Ultrakalte Moleküle (mit MO)

Q 6.2: Talk

Monday, March 2, 2009, 11:00–11:15, VMP 8 HS

Heteronuclear molecules in an ultracold Bose-Fermi Mixture — •Oliver Topic, Manuel Scherer, Thorsten Henninger, Carsten Klempt, Eberhard Tiemann, Wolfgang Ertmer, and Jan Arlt — Institut für Quantenoptik, Leibniz Universität Hannover, Germany

The prospect of investigating quantum degenerate molecules with a large dipole moment has driven the field of molecular physics for the past decade. The use of Feshbach resonances now allows for precise control of the interactions in heteronuclear mixtures of two atomic species and provides a new path towards such molecular ensembles.

Within our experiments, bosonic 87Rb atoms are used to cool an ensemble of fermionic 40K atoms to joint quantum degeneracy. This mixture provides the starting point for the detailed analysis and manipulation of the interactions. Applying a homogeneous magnetic field up to 700G allows for the investigation of heteronuclear Feshbach resonances in this mixture. We have been able to observe 28 resonances in ten different spin combinations. Together with results from molecular spectroscopy, this allowed for a large improvement of the interaction model. One of the observed resonances is used for the production of weakly bound heteronuclear Feshbach molecules. We report on a precise characterization of the production efficiency of ultracold Feshbach molecules and its dependence on critical parameters such as temperature and binding energy. Our analysis provides the first full theoretical understanding of this production efficiency and thus paves the way towards the optimised production of deeply bound molecular ensembles.