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TT: Fachverband Tiefe Temperaturen
TT 8: Transport: Quantum Dots, Wires, Point Contacts 1 (jointly with HL and O)
TT 8.1: Vortrag
Montag, 11. März 2013, 09:30–09:45, H20
Tunneling-induced renormalization in interacting quantum dots — •Janine Splettstoesser1, Michele Governale2, and Jürgen König3 — 1Institut für Theorie der Statistischen Physik, RWTH Aachen University — 2School of Physical and Chemical Sciences, Victoria University of Wellington, New Zealand — 3Theoretische Physik, Universität Duisburg-Essen, Germany
A single-level quantum dot with arbitrarily strong onsite Coulomb interaction weakly coupled to electronic reservoirs is studied. We here present an analysis of tunneling-induced quantum fluctuations, generating cotunneling processes and renormalizing system parameters. For a perturbative treatment of these quantum fluctuations in the limit of weak tunnel coupling, we remove off-shell parts of the Hamiltonian via a canonical transformation. We find that the tunnel couplings for the transitions connecting empty and single occupation respectively single and double occupation of the dot renormalize with the same magnitude but with opposite signs [1]. This has an important impact on the shape of the renormalization extracted for example from the conductance. Finally, we verify the compatibility of our results with a systematic second-order perturbation expansion of the linear conductance performed within a diagrammatic real-time approach.
[1] J. Splettstoesser, M. Governale, J. König, Phys. Rev. B 86, 035432 (2012).