Jeudi 02 octobre 2014 à 10h15
Salle 234, Ecole de Physique

Exact results on the out-of-equilibrium Kondo model

Edouard Boulat, Université Paris Diderot, France

Transport in nanoscale quantum devices can be described in some situations by quantum impurity models in which the low energy regime is often a strong coupling (SC) regime, the archetypical example maybe being the Kondo model. The description of the steady state resulting from biasing the baths is still an open problem in the generic case where interactions are present. In the case of integrable impurity models, it turns out that the exact solution *in equilibrium* cannot be straightforwardly extended to describe the out-of-equilibrium properties. We have recently developed a framework for integrable models [1], in which we can exactly tackle various out-of-equilibrium situations for quantum impurities in their SC regime, using their equilibrium integrability properties. It allows to compute directly the expansion of the universal scaling functions for physical quantities (like the electrical current), in principle to arbitrarily high order in the driving out-of-equilibrium, be it voltage, frequency, In particular, we show how to apply this to the Kondo model: our approach successfully goes beyond known results for the electrical current and noise. [1] L. Freton and E. Boulat, Phys. Rev. Lett. 112, 216802 (2014)