Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 4: CE: Quantum Impurities, Kondo Physics

TT 4.8: Talk

Monday, March 22, 2010, 12:15–12:30, H21

Discretization artifacts in the TD-NRG — •Fabian Güttge and Frithjof B. Anders — Technische Universität Dortmund, Lehrstuhl für Theoretische Physik II, 44221 Dortmund, Germany

One approach to study the nonequilibrium dynamics of quantum impurity systems is the time-dependent numerical renormalization-group (TD-NRG). Like the conventional NRG the TD-NRG relies on a logarithmic discretization of the bath continuum by mapping the bath onto a Wilson chain. We demonstrate in the real-time dynamics of a toy model, the resonant level model, that the group velocity of the wave propagation along the Wilson Chain is strongly position dependent. The induced reflection of waves corrupt the calculation of the time-dependent impurity occupation. The time period for which the occupation number is calculated reliably can be extended by using a hybrid approach combining different discretizations of the bath continuum.