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TT: Fachverband Tiefe Temperaturen

TT 12: Quantum Dynamics, Decoherence and Quantum Information (organized by DY)

TT 12.5: Talk

Monday, March 31, 2014, 11:00–11:15, HÜL 186

Beyond Born-Markov: validity, dependencies and the initial state problem — •Christian Karlewski, Michael Marthaler, and Gerd Schön — Institut für Theoretische Festkörperphysik, KIT, 76128 Karlsruhe

We expand the master equation for an open quantum system in terms of the Born and the Markov approximation. This makes it possible to calculate higher order-terms in the coupling strength to the bath beyond the famous Born-Markov approximation. Additionally, we are able to compare and distinguish between the terms belonging to Born or Markov approximation. The first issue we address with this approach is the initial state problem. Our method allows to quantify initial correlations and thus the error made by neglecting them. Secondly, we investigate the behaviour of a specific system, the spin boson model with an Ohmic noise with Drude-Lorentz cutoff, and we compare our computations with the Born-Markov approximation.