Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 74: Correlated Electrons: Quantum Impurities, Kondo Physics

TT 74.7: Talk

Wednesday, April 2, 2014, 16:30–16:45, BEY 81

Time Evolution of a Quantum Impurity System following a Quantum Quench at Finite Temperatures - a td-NRG Study — •Hoa Nghiem and Theodoulos A. Costi — Peter Grünberg Institut and Institute for Advanced Simulation, Research Centre Jülich, 52425 Jülich, Germany

To study the time evolution of an observable of a quantum impurity system after a sudden quench at an arbitrary temperature, we apply the recently developed time-dependent numerical renormalization group approach (td-NRG) to the Anderson model [1]. The quenches studied include switching from mixed valence to Kondo regime or vice versa, and from a uncorrelated to a correlated system or vice versa. We quantify the results in the short and long time limits by comparing them to the thermodynamic values in the initial and final states. We also present the time evolution due to general continuous pulses, acting in a finite time interval. The study is based on the generalization of td-NRG to a general pulse [1], where we consider the pulse as a sequence of smaller quenches, and formulate the time evolution following an arbitrary number of quenches.

[1] H. Nghiem and T. A. Costi, Preprint (2013).