Frankfurt 2006 – wissenschaftliches Programm

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SYRT: Radiation transport in random media

SYRT 2: Radiation transport in random media II

SYRT 2.4: Hauptvortrag

Freitag, 17. März 2006, 15:30–16:00, HVI

Nonlinear transport of matter waves through disorder potentials — •Peter Schlagheck — Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany

The rapid progress in technologies for trapping, cooling and manipulating ultracold atoms has lead to a number of fascinating experiments probing phenomena from condensed matter physics and nonlinear theory. A new direction in this context is the dynamics of Bose-Einstein condensates in disorder potentials, which can be induced with optical speckle potentials or on miniaturized magnetic waveguide geometries ("atom chips"), and which bears intriguing analogies to localization phenomena of electrons in solids as well as to the interplay of nonlinearity and disorder in the propagation of radiation. In our studies, we focus on the transport of a Bose-Einstein condensate through an atom-chip waveguide with smooth longitudinal disorder. We shall show that for weak atom-atom interactions an exponential (Anderson-like) decrease of the transmission with the sample length is obtained, where the localization length is reduced compared to the interaction-free case. For strong interactions, a cross-over to an algebraic (Ohm-like) decrease of the transmission is encountered, which correlates with the appearance of a permanently time-dependent scattering process of the condensate.