Nonequilibrium transport through a Kondo dot in a magnetic field:: Perturbation theory and poor man's scaling -: art. no. 076804

We consider electron transport through a quantum dot described by the Kondo model in the regime of large transport voltage V in the presence of a magnetic field B with max(V,B)>T-K. The electric current I and the local magnetization M are found to be universal functions of V/T-K and B/T-K, where T-K is the equilibrium Kondo temperature. We present a generalization of the perturbative renormalization group to frequency dependent coupling functions, as necessitated by the structure of bare perturbation theory. We calculate I and M within a poor man's scaling approach and find excellent agreement with experiment.