Condensed Matter Physics, 2007, vol. 10, No. 2(50), p. 235–248, English
Nonequilibrium perturbative formalism and spectral function for the Anderson model
(Department of Physics, Kyoto University, Kyoto 606-8502, Japan)
The present work is based on the nonequilibrium perturbative formalism. There the self-energies are derived up to the fourth-order. Consequently, it proves that the nonequilibrium(real-time) perturbative expansion can be connected with the Matsubara imaginary-time perturbative expansion for equilibrium.As the numerical results, the Kondo resonance still disappears for bias voltage exceeding the Kondo temperatures, as observed in experiments of two terminal systems.
nonequilibrium perturbative formalism, nonequilibrium Green's function, Kondo effect, Dyson's equation