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Q: Fachverband Quantenoptik und Photonik

Q 17: Quantengase: Bosonen Dynamik / Disorder

Q 17.7: Talk

Tuesday, March 3, 2009, 12:00–12:15, VMP 6 HS-A

Critical velocity of a Bose-Einstein condensate in presence of disorder — •Tobias Paul¹ and Mathias Albert² — ¹Institut für Theoretische Physik, Universität Heidelberg — ²Laboratoire de Physique Théorique et Modèles Statistiques, Université Paris Sud, Orsay

We investigate the breakdown and the critical velocity of the superfluid motion of a quasi-one-dimensional Bose-Einstein condensate in presence of disordered potentials. We present an analytical approach that relates the critical velocity beyond which the superflow breaks down with the statistical properties of the disorder potential. In particular, we study a) smoothly varying disordered potentials like the experimentally relevant case of an optical speckle potential, b) disordered potentials which consists of a series of individual scatterers. We compare our analytical results to full numerical computations which simulate the flow of the condensate through the disordered region.