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DY: Fachverband Dynamik und Statistische Physik

DY 8: Quantum Dynamics, Decoherence, and Quantum Information I

DY 8.1: Vortrag

Dienstag, 23. März 2010, 10:00–10:15, H38

Density dynamics in the anisotropic Heisenberg spin-1/2 chain at high temperatures: A current-autocorrelation approach to finite time and length scales — •Robin Steinigeweg — Institute for Theoretical Physics, Technical University of Braunschweig, Mendelsohnstr. 3, D-38106 Braunschweig, Germany

The transport of magnetization is investigated for the anisotropic Heisenberg spin-1/2 chain in the limit of high temperatures. The approach is essentially based on a connection between the evolution of the variance of an inhomogeneous nonequilibrium density and the current-autocorrelation function at finite times. Although this relationship is not restricted to the case of diffusive transport, it allows to extract a quantitative value for the diffusion constant in that case. By means of numerically exact diagonalization we indeed observe diffusive behavior for anisotropies which are larger than 1 and additionally confirm the diffusion coefficients which were obtained for these anisotropies from nonequilibrium bath scenarios.