Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 45: Correlated Electrons: Poster Session

TT 45.17: Poster

Donnerstag, 29. März 2012, 15:00–19:00, Poster B

Numerical Renormalization Group for dissipative quantum impurity systems — •Etienne Gärtner, Andrew Mitchell, and Ralf Bulla — Institute of Theoretical Physics, University of Cologne, Zuelpicherstr. 77, 50937 Cologne, Germany

The Numerical Renormalization Group (NRG) has been adapted to treat open dissipative quantum systems, but significant challenges remain. Certain models are well-described by this bosonic NRG in certain parameter regimes, but the essential requirement for Hilbert space truncation causes problems in other situations. Here we develop a novel extension of the regular bosonic NRG, employing an optimized basis to capture the important low-temperature physics in the smallest possible Hilbert space. We test the method with the paradigmatic spin-boson model, and go on to apply the method to a two-bath variant where truncation effects are typically more severe.