Hamburg 2009 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 17: Quantengase: Bosonen Dynamik / Disorder

Q 17.5: Talk

Tuesday, March 3, 2009, 11:30–11:45, VMP 6 HS-A

BEC’s in disordered potentials: from weak to strong localization — •Felix Eckert, Thomas Wellens, Viola Droujinina, and Andreas Buchleitner — Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3a, 79104 Freiburg

Recent numerical studies of BEC’s scattered from 2-D disordered potentials reveal a reduction (or even inversion) of the coherent back scattering (CBS) cone induced by the atomic mean-field interactions [1]. Since, at least in the linear case, enhanced backscattering corresponds to a reduction of the diffusion coefficient (weak localization), we now investigate whether this correspondence still holds in presence of atomic interactions. Employing a generalization of the self consistent approach of Vollhardt and Wölfle [2] in connection with the non-linear diagrammatic theory developed in [3], we calculate the diffusion coefficient for a BEC in a random finite medium, and study the transition from the weakly to the Anderson localized regime for different coupling constants of the interacting atoms in the BEC.

[1] M. Hartung et al., Phys. Rev. Lett. 101, 020603 (2008)

[2] D. Vollhardt and P. Wölfle, Phys. Rev. B 22, 4666 (1980)

[3] T. Wellens and B. Grémaud, Phys. Rev. Lett. 100, 033902 (2008)