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TT: Fachverband Tiefe Temperaturen

TT 47: Poster Session Correlated Electrons 2

TT 47.30: Poster

Mittwoch, 18. März 2020, 15:00–19:00, P2/3OG

Restoring the continuum limit in the time-dependent numerical renormalization group approach — •Jan Böker and Frithjof Anders — TU Dortmund, Theoretische Physik II, Otto-Hahn-Straße 4, 44227 Dortmund

We analytically construct a set of additional reservoirs coupled to the Wilson chain to recover the original continuous coupling functions to a quantum impurity.
We present a hybrid time-dependent numerical renormalization group (TD-NRG) approach which combines an accurate NRG treatment of the non-equilibrium dynamics on the finite size Wilson chain with a Bloch-Redfield formalism to include the effect of the additional reservoirs. For the solution of the Lindblad-style master equations a Lanczos method is employed. Our proposed approach tackles the intrinsic shortcoming of the TD-NRG induced by the bath discretization with a Wilson parameter Λ > 1. The effects of conservation laws and charge reflections along the Wilson chain are damped due to dissipation into the reservoirs, and a correct thermalization even on longer timescales is reached. The presented hybrid TD-NRG approach is used to investigate the real-time nonequilibrium dynamics in fermionic quantum-impurity systems. An analytical solution of the resonant-level model (RLM) serves as a benchmark for the accuracy of the method which is then applied to non-trivial models, such as the interacting RLM and the single impurity Anderson model.