Hannover 2003 – scientific programme

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Q: Quantenoptik

Q 48: Poster: Fallen und Kühlung

Q 48.10: Poster

Thursday, March 27, 2003, 16:30–18:30, Lichthof

Interactions between two atomic species in an optical dipole trap — •Matthias Staudt, Marcel Mudrich, Stephan Kraft, Jörg Lange, Marc Eichhorn, Roland Wester, and Matthias Weidemüller — Max-Planck-Institut für Kernphysik, 69029 Heidelberg

Interactions between ultracold atoms in the electronic groundstate can be studied under nearly ideal conditions in a quasi-electrostatic dipole trap (QUEST) since resonant light is absent. In our experiments, cesium and lithium atoms are stored separately or simultaneously in such a trap formed by the focus of a 100 W CO₂-laser beam.

Elastic collisions between the two species in the lowest hyperfine state lead to sympathetic cooling of lithium atoms in thermal contact with an ensemble of colder cesium atoms [1]. If the atoms are stored in the upper hyperfine level of the ground state, spin-changing collisions lead to trap loss due to the release of internal energy. Here, we present detailed studies of both homonuclear and heteronuclear inelastic processes. The non-exponential decrease in density is well fitted by a simple model for inelastic binary collisions taking into account relaxation heating. Inferred rate coefficients are in good agreement with theoretical predictions.

Besides, comparative studies of homonuclear photoassociative spectroscopy are performed on the cesium sample in the QUEST and in a magneto-optical trap.

[1] M. Mudrich et al., Phys. Rev. Lett. 88, 253001 (2002)