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TT: Fachverband Tiefe Temperaturen

TT 4: CE: Quantum Impurities, Kondo Physics

TT 4.7: Vortrag

Montag, 22. März 2010, 12:00–12:15, H21

Relaxation vs decoherence: Spin and current dynamics in the anisotropic Kondo model at finite bias and magnetic field — •Mikhail Pletyukhov, Dirk Schuricht, and Herbert Schoeller — Institut für theoretische Physik A, RWTH Aachen, Germany

Using a nonequilibrium renormalization group method we study the real-time evolution of spin and current in the anisotropic Kondo model (both antiferromagnetic and ferromagnetic) at finite magnetic field h₀ and bias voltage V. We derive analytic expressions for all times in the weak-coupling regime max{V,h₀,1/t}≫ T_c (T_c= strong coupling scale). We find that all observables decay both with the spin relaxation and decoherence rates Γ_1/2. Various V-dependent logarithmic, oscillatory, and power-law contributions are predicted. The low-energy cutoff of logarithmic terms is generically identified by the difference of transport decay rates. For small times t≪ max{V,h₀}⁻¹, we obtain universal dynamics for spin and current.