Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 111: Correlated Electrons: Quantum Impurities, Kondo Physics
TT 111.7: Talk
Friday, March 20, 2015, 11:15–11:30, H 3005
From the weak coupling regime to the Kondo crossover within the reduced density matrix framework — •Davide Mantelli and milena grifoni — Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Deutschland
When an Anderson quantum impurity is coupled to non interacting leads, many different regimes are accessible. In the weak coupling regime Γ≪ kBT,U (with Γ the tunnelling coupling, T the temperature and U the charging energy), Coulomb blockade and co-tunnelling phenomena are well described within a perturbative approach in Γ. However, as the thermal energy approaches the coupling one, the perturbative method breaks down. By summing up a series of charge fluctuations events to all order in Γ we managed to reach the intermediate regime (Γ≃ kBT) within the so-called “Dressed Second Order” (DSO)[1]. Considering its natural extension, the “Dressed-DSO”, we achieved to describe the Kondo crossover where the thermal energy is comparable to the Kondo one (T≃ TK). In this regime, equilibrium and non equilibrium fingerprints of the Kondo physics are carefully analysed.
[1] J. Kern and M. Grifoni, Eur. Phys. J. B 86, 384 (2013)