| We deal with the nonequilibrium two-lead Anderson model which is believed to describe transport through a d-c biased quantum dot. We analyze the decoherence induced by a bias voltage V and study their effects on the density of states and the evolution of the differential conductance with the bias voltage. The low-bias differential conductance is found to be a universal function of the normalized bias voltage V/T_K, where T_K is the Kondo temperature. The universal scaling with a single energy scale T_K at low bias voltages is also observed for the renormalized decoherence rate. Finally we will discuss the effect of the decoherence rate on the crossover from strong to weak coupling regime when either the temperature or the bias voltage is increased. |
|