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Q: Fachverband Quantenoptik und Photonik
Q 3: Quantengase: Dynamik in Gittern
Q 3.5: Vortrag
Montag, 2. März 2009, 11:45–12:00, VMP 6 HS-A
Collapse and Revival of Matter Waves in Bosonic Optical Lattices — •Francisco Ednilson Alves dos Santos1 and Axel Pelster1,2 — 1Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 2Fachbereich Physik, Universität Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
Within the Ginzburg-Landau theory of the Bose-Hubbard model [1], we derive the underlying equation of motion which describes the dynamics of the condensate wave function. With this we describe theoretically the experimental results of Ref. [2], in particular the apparent damping effect which completely extinguishes the matter wave after a characteristic time scale. We show that, due to the overall harmonic potential which confines the atoms inside a finite volume, the condensate wave function oscillates with frequencies which vary slightly from site to site. As time elapses, the values of the matter wave at two spatially separated points in the lattice become out of phase. This destroys the coherence of the condensate after a certain damping time which is associated with the harmonic frequency of the external magnetic trap.
[1] B. Bradlyn, F.E.A. dos Santos, and A. Pelster, Phys. Rev. A (in press), eprint: arXiv:0809.0706.
[2] M. Greiner, O. Mandel, T. W. Hänsch, and I. Bloch, Nature, 419, 51 (2002).