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TT: Fachverband Tiefe Temperaturen

TT 22: Transport: Poster Session

TT 22.62: Poster

Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B

Investigations on transport properties of modular quantum systems based on a perturbative expansion of the current-autocorrelation function — •Christian Bartsch and Jochen Gemmer — Fachbereich Physik, Universität Osnabrück, Barbarastrasse 7, D-49069 Osnabrück, Germany

The dynamics of the spatial variance of the deviation of some density (particles, energy, etc.) from equilibrium can be expressed in terms of the dynamics of the current-autocorrelation function, that also appears in the Kubo formula (see also talk J. Gemmer). We present a systematic perturbation expansion for the current-autocorrelation function whose leading order is based on the diagonalization of finite parts of the system.

Additionally, we introduce a numerically feasible approximation for the next higher order to estimate if and for what times the leading order can be expected to give an adequate description. The analysis is supported by numerical calculations for concrete models.