•Markus Keil¹ und Herbert Schoeller^2
2Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe
¹Institut für Theoretische Physik, Universität Göttingen, 37073 Göttingen

Using a real-time renormalization group method we determine the complete dynamics of the spin-boson model with ohmic dissipation for coupling strengths a < 0.1-0.2. We calculate the relaxation and dephasing time, the static susceptibility and correlation functions. Our results are consistent with quantum Monte Carlo simulations and the Shiba relation. We present for the first time reliable results for finite cutoff and finite bias in a regime where perturbation theory in a or in tunneling breaks down. Furthermore, an unambigious comparism to results from the Kondo model is achieved.