Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 37: Transport: Quantum dots, wires, point contacts 3 (TT, jointly with HL)

HL 37.4: Vortrag

Dienstag, 12. März 2013, 10:15–10:30, H20

Superfermions in Liouville space as a powerful tool for investigating quantum transport out of equilibrium: new insights into the Anderson model — •Roman Saptsov^1,2 and Maarten Wegewijs^1,2,3 — ¹Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany — ²JARA- Fundamentals of Future Information Technology — ³Institute for Theory of Statistical Physics, RWTH Aachen, 52056 Aachen, Germany

Recently, we introduced a new formalism of superfermions in Liouville space for a renormalization group study of the non-linear transport through an Anderson quantum dot (QD) at zero temperature [1]. This formalism turns out to be a very useful tool to study other aspects of non-equilibrium phenomena, as well. In the wide band limit for a strongly interacting QD it allows one to sum up exactly temperature-independent contributions and obtain a general form of the QD effective Liouvillian as well as some exact relations for its eigenvalues. In the non-interacting case, U=0, our approach describes time evolution of the QD in the most simple way: we show that a "Pauli super-exclusion principle" for the superfermions leads to the exact truncation of the time-dependent perturbation series at the second order in a coupling constant. Using our approach we are able also to explore the time-evolution of the initial dot-reservoir correlations. We discuss the extension of this U=0 result to the case of finite U. Finally, we discuss other useful applications of our formalism, such as: path integrals in Liouville space and "super- mean-field theory".
[1] R.B. Saptsov, M.R. Wegewijs, arXiv:1207.3207