Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 42: Coherent Quantum Dynamics (joint session DY/TT)

DY 42.12: Talk

Thursday, March 23, 2017, 12:45–13:00, ZEU 160

Spectral functions of quantum impurity models in the long-time limit of the time-dependent numerical renormalization group approach — •Theo Costi and Hoa Nghiem — Peter Grünberg Institut (PGI-2) and Institute for Advanced Simulation IAS-3), Forschungszentrum Jülich, Jülich, Germany

We develop a new multiple-quench time dependent numerical renormalization group (TDNRG) approach to study the time-evolution of strongly correlated quantum impurities in response to quantum quenches, pulses and periodic driving fields with potential application to a number of fields, including cold atom systems, non-equilibrium transport in nanoscale devices, and the theory of pump-probe spectroscopies of correlated materials within the non-equilibrium dynamical mean field theory. While the single-quench TDNRG suffers from sizeable errors for spectral functions and thermodynamic observables in the long-time limit, we show that our new multiple-quench TDNRG approach systematically reduces these errors to negligible values. Precise results are presented for local observables of the Anderson model, both static (local occupation and double occupancy) and dynamic (spectral function), in the long-time limit. For finite times and periodic driving, we demostrate a significant improvement for the time evolution of the local occupation as compared to our previous approach [1].

[1] H. T. M. Nghiem, T. A. Costi, Phys. Rev. B90, 035129 (2014).