Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 15: Controlling Dirty Bosons: Disorder Effects on BECs

DY 15.1: Talk

Tuesday, February 26, 2008, 14:30–14:45, MA 001

Bose-Einstein Condensates in Strongly Disordered Traps — •Thomas Nattermann¹ and Valery Pokrovsky² — ¹Institut für theoretische Physik der Universität zu Köln — ²Department of Physics, Texas A&M University, USA

A Bose-Einstein condensate in an external potential consisting of a superposition of a harmonic and a random potential is considered theoretically. From a semi-quantitative analysis we find the size, shape and excitation energy as a function of the disorder strength. For positive scattering length and sufficiently strong disorder the condensate decays into fragments each of the size of the Larkin length L. This state is stable over a large range of particle numbers. The frequency of the breathing mode scales as 1/L^2. For negative scattering length a condensate of size L may exist as a metastable state. These findings are generalized to anisotropic traps.