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DY: Fachverband Dynamik und Statistische Physik

DY 35: ISS Transport and Localization of interacting Bosons II

DY 35.5: Vortrag

Donnerstag, 17. März 2011, 15:30–15:45, BAR Schön

Destruction of localization in a nonlinear generalization of the quantum kicked rotor — •Goran Gligorić, Joshua Bodyfelt, and Sergej Flach — MPI für Physik komplexer Systeme

Quantum suppression of classically chaotic diffusion was first observed numerically in the quantum kicked rotor model. This phenomenon can be considered in many aspects as the dynamical version of Anderson localization in tight-binding disordered models [1]. In the case of the kicked rotor there is no true randomness and diffusion after an initial time interval appears, resulting from chaotic dynamics in the corresponding classical counterpart. The realization of Bose-Einstein condensates has opened a new opportunity for studying dynamical systems in the presence of many-body interactions. In the mean field approximation, these interactions can be represented by adding a quartic nonlinearity in the Schrödinger equation. Our aim is to utilize such a model, as introduced by Shepelyansky [2] in order to understand how nonlinearity generally affects the kicked rotor model. Particularly, we aim to understand the influence of nonlinearity on dynamical localization; of special concern is the possibility of a critical nonlinear strength above which localization is destroyed, and how this destruction comes about. Lastly, we will consider the corresponding anomalous subdiffusion law in this regime and test its universality.

[1] S. Fishman, D.R. Grempel and R.E. Prange, Phys. Rev. A 29 (1984) 1639

[2] D.L. Shepelyansky, Phys. Rev. Lett. 70 (1993) 1787