Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 12: Poster Session Superconductivity

TT 12.15: Poster

Montag, 11. März 2013, 15:00–19:00, Poster D

Resummation approach to interacting quantum dots in contact with superconducting leads — David Futterer¹, •Jacek Swiebodzinski¹, Michele Governale², and Jürgen König¹ — ¹Theoretische Physik, Universität Duisburg-Essen and CENIDE, 47048 Duisburg, Germany — ²School of Chemical and Physical Sciences and MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand

The simultaneous occurrence of Coulomb interactions and superconducting correlations combined with a possible non-equilibrium situation makes interacting quantum dots (QD) that are coupled to superconductors a fascinating field of research. To account for all these features in a theoretical description proves however challenging and one has to resort to specific approximations or numerically demanding solving schemes. Here, we consider a QD coupled to one normal and two superconducting leads. We first calculate the transport properties of the system using a perturbative expansion in the dot-normal reservoir coupling. We allow for a finite superconducting gap Δ by performing a 1/Δ expansion. We then introduce an approach based on partial resummation of diagrams to infinite order in the coupling and calculate the Andreev bound states of the system. The results on the latter show very good agreement with those obtained by the computationly more demanding numerical renormalization group method.