Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 13: Transport: Poster Session
TT 13.14: Poster
Montag, 26. März 2012, 15:00–19:00, Poster B
Liouville space formulation for interacting quantum dots with superconducting leads — •Jacek Swiebodzinski1, Dirk Schuricht2, Jürgen König1, and Herbert Schoeller2 — 1Theoretische Physik, Universität Duisburg-Essen and CeNIDE, 47048 Duisburg, Germany — 2Institut für Theorie der Statistischen Physik, RWTH Aachen, 52056 Aachen, Germany
Following recent advances in nanofabrication, quantum dots in contact with superconducting leads have increasingly moved into the focus of spintronic related research. A key issue is hereby the occurrence of both superconducting correlations and Coulomb interaction combined with a general non-equilibrium situation. In the following contribution we present a diagrammatic method suitable to describe quantum dots with arbitrarily large interactions coupled to normal and superconducting leads. In the latter case transport can be provided either by quasiparticle or Andreev tunneling giving rise to a rich variety of interesting physical phenomena. The method is based upon a perturbative expansion in the dot-reservoir coupling and formulated in Liouville space. As compared to the standard diagrammatic approach in Keldysh space, in the Liouville formulation the two branches of the Keldysh contour are taken together simplifying the diagrammatic language. Relaxation and dephasing rates can be easily read off from the poles of the Liouvillian. We apply the method to a normal lead - quantum dot - superconductor system discussing some of its properties.