New interpolative treatment of the single-impurity Anderson model

The many-body quasi-particle dynamics of the single-impurity Anderson model is investigated by means of the equations of motion for the higher-order Green's functions. It is shown that an interpolating approximation, which simultaneously reproduces the weak-coupling limit up to second order in the interaction strength U and the strong-coupling limit up to second order in the hybridization V (and thus also fulfils the atomic limit) can be formulated self-consistently