Low-energy properties of an out of equilibrium Anderson model

Abstract

The Anderson impurity model is studied under a finite bias voltage V applying a microscopic theory of the local Fermi-liquid by Yamada and Yosida to the Keldysh diagrammatic formalism. Using the Ward identities for the nonequilibrium Green's functions, the low-energy behavior of the self-energy has been deduced exactly up to terms of order ω 2, T 2 and V 2. The coefficients are defined with respect to the equilibrium ground state, and contain all contributions of the Coulomb interaction U. In this report, we examine the U dependence of the spectral function and differential conductance in the vicinity of the equilibrium by computing the coefficients explicitly with the Bethe ansatz solution in the electron–hole symmetric case.