Düsseldorf 2007 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 64: Poster Quantengase

Q 64.27: Poster

Donnerstag, 22. März 2007, 16:30–18:30, Poster C

Collective Excitations in a Trapped Bose-Einstein Condensate with Weak Quenched Disorder — •Giovanni Falco, Axel Pelster, and Robert Graham — Fachbereich Physik, Universität Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany

We study how the collective mode frequencies of a condensate in a harmonic trap are shifted by the presence of additional weak quenched disorder. To this end we apply the Huang-Meng theory [1] to an inhomogeneous condensate in the Thomas-Fermi approximation. This approach describes how local condensates in the minima of the disorder potential interfere with the superfluid properties of the condensate. The consequences for the hydrodynamic equations are worked out in detail. We find that the negative shifts of the collective frequencies for the monopole and the dipole mode decrease rapidly with increasing correlation length of the disorder potential, at least if we assume that its the spatial correlation function is a Gaussian. Thus, our theory makes it possible to experimentally test the predictions of the Huang-Meng theory.

[1] K. Huang and H.F. Meng, Phys. Rev. Lett. 69, 644 (1992)