Düsseldorf 2007 – wissenschaftliches Programm

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SYMC: Symposium Molecular Collisions at ultracold temperatures

SYMC 1: Molecular collisions at ultracold temperatures I

SYMC 1.4: Hauptvortrag

Montag, 19. März 2007, 15:30–16:00, 5D

Ultracold molecules in an optical lattice — •Johannes Hecker Denschlag — Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria

An optical lattice is an excellent environment to produce, manipulate and study ultracold molecules. We describe recent experiments where we have created a pure ultracold ensemble of Rb₂ dimers in various well defined quantum states in the electronic ground state. Starting from an atomic ⁸⁷Rb condensate which is adiabatically loaded into a 3D optical lattice we first create Feshbach molecules by ramping over a Feshbach resonance. A purification scheme based on a combined laser and radiofrequency pulse removes all unbound atoms. Using optical STIRAP (stimulated Raman adiabatic passage) or a radio frequency sweep, we can efficiently transfer these Feshbach molecules to a more deeply bound vibrational level. In this way we create well defined mixtures and coherent superpositions of molecular states which can later be used to invesigate molecular interactions and collisions. Besides studying chemically bound molecules, optical lattices also allow forming a novel kind of stable bound state of two atoms which is based on repulsion rather than attraction between the particles. We will explain how these lattice-induced repulsively bound atom pairs come about and discuss their interesting properties.