Mikhail Pletyukhov, Herbert Schoeller
We analyze the nonequilibrium Kondo model at finite voltage and temperature
by using a new formulation of real-time renormalization group with the Laplace
variable as flow parameter. We evaluate the energy-dependent spin relaxation
rate and nonlinear conductance, and propose a universal line shape for the
latter in the whole crossover regime from weak to strong coupling. The results
are shown to agree well with exact methods in equilibrium, Fermi liquid theory,
weak-coupling expansions, and recent experiments. For the spin relaxation
dynamics we find a universal exponential decay in the long-time limit along
with a truncation-dependent pre-exponential power-law. For multi-channel models
a pure power-law decay typical for non-Fermi liquid behaviour is predicted.
View original:
http://arxiv.org/abs/1201.6295
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