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MO: Fachverband Molekülphysik

MO 1: Ultrakalte Moleküle (mit Q)

MO 1.6: Vortrag

Montag, 2. März 2009, 12:00–12:15, VMP 8 HS

Observation of a resonant exchange reaction in an ultracold mixture of cesium atoms and dimers — •Martin Berninger¹, Francesca Ferlaino¹, Steven Knoop¹, Walter Harm¹, Michael Mark^1,2, Hanns-Christoph Nägerl¹, and Rudolf Grimm^1,3 — ¹Institut für Experimentalphysik, Universität Innbruck, Austria — ²Swinburne University of Technology, Melbourne, Australia — ³Institut für Quantenoptik und Quanteninformation, Innsbruck, Austria

An ultracold atomic gas of cesium is a versatile system to study few-body phenomena because of the extreme tunability of its scattering length. We have studied interactions in an optically trapped mixture of Feshbach molecules with atoms, realized in a Cs gas at nanokelvin temperatures. We start with a sample of atoms in the lowest hyperfine state A and produce molecules AA by means of Feshbach association. Then we transfer the remaining atoms A to a hyperfine state B that is distinct from that of the Feshbach molecule’s constituents. We study the exchange reaction B + AA → A + AB, which is resonantly enhanced when the binding energies of AA and AB are equal. The reaction rate is prominent and magnetically tunable, thus showing all properties of controllable ultracold chemistry.