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TT: Fachverband Tiefe Temperaturen
TT 46: Correlated Electrons: Quantum Impurities, Kondo Physics
TT 46.7: Vortrag
Freitag, 27. März 2009, 12:00–12:15, HSZ 301
Real-time renormalization group in frequency space: A complete 2-loop analysis of the nonequilibrium anisotropic Kondo model at finite magnetic field — Herbert Schoeller1,2 and •Frank Reininghaus1,2 — 1Institut für Theor. Physik A, RWTH Aachen University, Germany — 2JARA-Fundamentals of Future Information Technology
We use a recently developed real-time renormalization group method in frequency space (RTRG-FS) to describe nonequilibrium phenomena in generic fermionic quantum system coupled weakly to several reservoirs via spin and/or orbital fluctuations. Within a 2-loop analysis we derive analytic formulas for the nonlinear conductance and the kernel determining the time evolution of the reduced density matrix. We apply the general formalism to the nonequilibrium anisotropic Kondo model at finite magnetic field. Besides the nonlinear conductance and the magnetic susceptibility, we calculate for the first time the spin relaxation and dephasing rates and the renormalized g-factor beyond leading order. Furthermore, we show in all orders in the exchange coupling that the RG flow of the vertices is cut off by relaxation and dephasing rates.