Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 102: Transport: Quantum Dots, Quantum Wires, Point Contacts 2 (jointly with HL)

TT 102.9: Vortrag

Donnerstag, 19. März 2015, 17:30–17:45, A 053

Nonequilibrium transport through Anderson impurities: A comparative study based on continuous-time quantum Monte Carlo simulations and hierarchical quantum master equations — •Rainer Härtle1, Guy Cohen2, David R. Reichman2, and Andrew J. Millis31Institut für theoretische Physik, Georg-August-Universität Göttingen, Göttingen, Germany — 2Department of Chemistry, Columbia University, New York, USA — 3Department of Physics, Columbia University, New York, USA

The hierarchical quantum master equation approach [1,2] is a promising new method for describing quantum impurity systems under nonequilibrium conditions. It employs a hybridization expansion with an advanced truncation scheme [2] to determine the time evolution of the impurity’s density matrix from a product initial state. The method is a systematic expansion for which convergence can be demonstrated so that numerically exact results can in principle be obtained. To elucidate the rigor of this procedure, we study the nonequilibrium dynamics of an Anderson impurity and benchmark the results with respect to continuous time quantum Monte Carlo methods [3]. The comparison shows excellent agreement as long as the temperature is above the Kondo scale. A discussion of the computational burden and of the scaling of numerical errors with truncation level is given. New results are presented for long-time dynamics arising in the presence of a magnetic field and/or an asymmetric coupling to leads.

[1] J. Jin et al., JCP 128, 234703 (2008).

[2] R. Härtle et al., PRB 88, 235426 (2013).

[3] G. Cohen et al., PRB 87, 195108 (2013).

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