Regensburg 2007 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 24: Poster I

DY 24.3: Poster

Mittwoch, 28. März 2007, 16:00–18:00, Poster D

Transport properties of finite quantum systems — •Christian Bartsch and Jochen Gemmer — Physics Department, University of Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany

It has been observed that normal transport behaviour can appear in finite quantum systems for certain quantities. This means, the dynamics of these quantities are statistical, i.e. they are controlled by rate equations, although the time evolution of the complete system is generated by the Schrödinger Equation. The exponential relaxation can be described correctly by the Hilbert Space Average Method (HAM) [1] or the time-convolutionless (TCL) projection operator technique [2]. Both methods also yield some necessary criteria for the occurrence of normal transport concerning rough system parameters like bandwidths and average interaction strengths. Additionally, the structure of the interaction must be taken into account, too. One possibility is to check if the squared interaction matrix is essentially diagonal, which seems to be a crucial feature for statistical decay to occur. A similar approach was proposed by van Hove in [3] for continuous systems. Alternatively, one can evaluate higher orders of the TCL expansion and determine the magnitude of the deviation from the rate equations.
1 J. Gemmer, M. Michel, G. Mahler, Quantum Thermodynamics, Springer (2004)
2 H.-P. Breuer, F. Petruccione, The Theory of Open Quantum Systems, Oxford (2002)
3 L. van Hove, Physica XXI 517 (1955)