Düsseldorf 2007 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 72: Ultrakalte Moleküle II (gemeinsam mit MO)
Q 72.2: Talk
Friday, March 23, 2007, 14:30–14:45, 6J
Resonant enhancement in ultracold atom-dimer scattering — •Steven Knoop1, Michael Mark1, Francesca Ferlaino1, Johann Georg Danzl1, Harald Schöbel1, Tobias Kraemer1, Hanns-Christoph Nägerl1, and Rudi Grimm1,2 — 1Institut für Experimentalphysik, Universität Innsbruck, Austria — 2Institut für Quantenoptik und Quanteninformation, Innsbruck, Austria
Ultracold quantum gases with tunable interaction yield the unique possibility to study universal properties of resonantly interacting few-body systems. A clear example has been the experimental evidence for Efimov quantum states in an ultracold Cs gas [1]. Their signature was found in a giant three-body loss feature due to resonant coupling between three free atoms and an Efimov trimer. Following the Efimov scenario an Efimov trimer can also couple to an atom and a dimer [2].
Here we will report on the experimental observation of resonant enhancement in the inelastic atom-dimer collision rate. By means of Feshbach association ultracold dimers in a weakly bound s-wave state are produced and trapped in an optical dipole trap [3]. Together with the remaining atoms they form an atom-dimer mixture which is at a temperature of 250 nK. By selectively measuring the loss of dimers the inelastic atom-dimer collision rate is obtained. A resonance in the collision rate at a scattering length of 400 Bohr radii is found which might represent an atom-dimer Efimov resonance.
[1] T. Kraemer et al, Nature 440, 315 (2006); [2] E. Braaten and H.-W. Hammer, Phys. Rep. 428, 259 (2006); [3] M. Mark et al, submitted to PRA (2007)