Kondo resonance in a quantum dot: Finite-U Anderson model out of equilibrium

The transport properties through a quantum dot are studied by using the fin ite-Li Anderson model. The nonequilibrium Kondo resonance is investigated b y the perturbation expansion in a power series of the Coulomb repulsion U i n the dot at zero temperature. The current conservation is realized by the introduction of an effective distribution function in the dot. It is found that the Kondo peak in the density of states is not split by an applied vol tage bias, which is in accord with the experiments to date.