Dresden 2009 – wissenschaftliches Programm

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SYAL: Symposium Anderson Localization in Nonlinear and Many-Body Systems

SYAL 1: Anderson Localization in Nonlinear and Many-Body Systems

SYAL 1.6: Hauptvortrag

Montag, 23. März 2009, 16:30–17:00, BAR SCHÖ

Single-particle and many-body Anderson localizations with Bose-Einstein condensates — •Laurent Sanchez-Palencia — Laboratoire Charles Fabry de l'Institut d'Optique, 2, avenue Augustin Fresnel, Palaiseau, F-91128, France

We present our recent theoretical and experimental works on the expansion of a Bose-Einstein condensate in a disordered potential. We show that a such a system can exhibit single-particle Anderson localization under conditions that we will discuss. We determine analytically the localization and find that experimental data are in very good agreement. In addition, we show that the one-dimensional speckle potentials used in the experiments are very peculiar as they exhibit an effective mobility edge.

We also investigate the effects of disorder in a Bose-Einstein condensate at equilibrium in a regime where the interaction energy dominates over the kinetic energy. While the ground state is extended owing to the strong interactions, we show that the elementary excitations of the condensate (Bogolyubov quasi-particles) are localized. This constitutes an exemple of many-body Anderson localization in a system with strong meanfield interactions. We present a general formalism to determine analytically the localization lengths and compare them to numerical calculations in 1D.