Ruprecht-Karls-Universität Heidelberg
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Andreas Mielke
Institut für Theoretische Physik
Ruprecht-Karls Universität
Philosophenweg 19
D-69120 Heidelberg
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Stefan Kehrein, Andreas Mielke: Low temperature equilibrium correlation function in dissipative quantum systems
Ann. Physik (Leipzig)6, 90-135 (1997) .

Archiv: cond-mat/9607160


We introduce a new theoretical approach to dissipative quantum systems. By means of a continuous sequence of infinitesimal unitary transformations, we decouple the small quantum system that one is interested in from its thermodynamically large environment. This yields a trivial final transformed Hamiltonian. Dissipation enters through the observation that generically observables 'decay' completely under these unitary transformations, i.e. are completely transformed into other terms. As a nontrivial example the spin-boson model is discussed in some detail. For the super-Ohmic bath we obtain a very satisfactory description of short, intermediate and long time scales at small temperatures. This can be tested from the generalized Shiba-relation that is fulfilled within numerical errors.


author="Stefan Kehrein, Andreas Mielke",
title="Low temperature equilibrium correlation function in dissipative quantum systems",
journal="Ann. Physik (Leipzig)",

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Letzte Änderung: 25.3.2024.