Berlin 2008 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 10: Internal Symposium: Controlling Dirty Bosons: Disorder Effects on BECs
DY 10.4: Vortrag
Dienstag, 26. Februar 2008, 10:55–11:20, MA 001
Collective Excitations in a Trapped Bose-Einstein Condensate with Weak Quenched Disorder — •Gianmaria Falco1, Axel Pelster2, and Robert Graham2 — 1Department of Physics, Cologne University, Zülpicher Straße 77, 50937 Köln, Germany — 2Fachbereich 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 [1,2] to an inhomogeneous condensate in the Thomas-Fermi approximation [3]. This approach describes how local condensates in the minima interfere with the superfluid property of the condensate. We work out in detail the consequences for the hydrodynamic equations. In case of a Gaussian correlated disorder correlation we find that the negative shifts of the collective frequencies for the monopole and the dipole mode decrease rapidly with increasing correlation length. 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)
[2] G.M. Falco, A. Pelster, and R. Graham, Phys. Rev. A 75, 063619 (2007)
[3] G.M. Falco, A. Pelster, and R. Graham, Phys. Rev. A 76, 013624 (2007)