Low temperature equilibrium correlation functions in dissipative quantum systems
摘要
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.
引用
@article{arxiv.cond-mat/9607160,
title = {Low temperature equilibrium correlation functions in dissipative quantum systems},
author = {Stefan K. Kehrein and Andreas Mielke},
journal= {arXiv preprint arXiv:cond-mat/9607160},
year = {2016}
}
备注
38 pages, LaTeX2e, seven postscript figures included, figure 8 is available on request from one of the authors (A.M.). The revised version contains minor changes, it will appear in this form in Ann. Physik (Leipzig) 1996