Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 7: Correlated Electrons - (General) Theory II

TT 7.6: Vortrag

Freitag, 4. März 2005, 18:00–18:15, TU H2053

Violation of the Fluctuation-Dissipation Theorem in the Kondo Model with a Non-Equilibrium Initial State — •Dmitry Lobaskin and Stefan Kehrein — Theoretische Physik III - Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg

The fluctuation-dissipation theorem (FDT) plays a fundamental role in understanding equilibrium quantum many-body problems. However, the FDT does in general not hold in non-equilibrium situations. In this talk we present exact results for the violation of the FDT in the Kondo model where the impurity spin is frozen for all negative times, and set free to relax towards its equilibrium value at positive times. Exact results at the Toulouse point of this model (cond-mat/0405193) make it possible to investigate the FDT violation on all time scales: for times much later than the initial non-equilibrium preparation, for times immediately after the relaxation starts, and for the crossover between these two regimes. General aspects of the FDT and the reason for its violation in non-equilibrium are discussed as well.