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DY: Fachverband Dynamik und Statistische Physik

DY 6: Poster Session I

DY 6.4: Poster

Montag, 22. März 2010, 16:00–18:00, Poster B2

Quantum corrections in the strong friction limit: Perturbation theory and applications — •Stefan A. Maier and Joachim Ankerhold — Institut für Theoretische Physik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany

The strong friction regime at low temperatures is analyzed systematically starting from the formally exact path integral expression for the reduced dynamics. This quantum Smoluchowski regime allows for a type of semiclassical treatment in the inverse friction strength so that higher order quantum corrections to the original quantum Smoluchowski equation [PRL 87, 086802 (2001), PRL 101, 11903 (2008)] can be derived. Drift and diffusion coefficients are determined by the equilibrium distribution in position and are directly related to the corresponding action of extremal paths and fluctuations around them. The inclusion of higher order corrections reproduces the quantum enhancement above crossover for the decay rate out of a metastable well exactly. Our results are also applied to study transport in quantum ratchets.