The asymmetric single-impurity Anderson model – the modified perturbation theory

The asymmetric single - impurity Anderson model – the modified perturbation theory

——————————————————————————————————————— Abstract We investigate the single-impurity Anderson model by means of the recently introduced modified perturbation theory. This approximation scheme yields reasonable results away from the symmetric case. The agreement with exactly known results for the symmetric case is checked, and results for the non-symmetric case are presented. With decreasing cond...

2 8 Ju n 20 01 Renormalized perturbation calculations for the single impurity Anderson model

We illustrate the renormalized perturbation expansion method by applying it to a single impurity Anderson model. Previously, we have shown that this approach gives the exact leading order results for the specific heat, spin and charge susceptibilities and leading order temperature dependence of the resistivity for this model in the Fermi-liquid regime, when carried out to second order in the re...

Size and dimensionality effect in single-impurity Anderson model

Non-Fermi-liquid theory of a compactified Anderson single-impurity model.

We consider a version of the symmetric Anderson impurity model (compactified) which has a non-Fermi liquid weak coupling regime. We find that in the Majorana fermion representation the perturbation theory can be conveniently developed in terms of Pfaffian determinants and we use this formalism to calculate the impurity free energy, self energies, and vertex functions. We also derive expressions...

The energy-scale-dependent composite operator method for the single-impurity Anderson model

The recently developed energy-scale-dependent Composite Operator Method is applied to the single-impurity Anderson model. A fully self-consistent solution is given and analyzed. At very low temperatures, the density of states presents, on the top of the high-energy background, a Kondo-like peak whose parameter dependence is discussed in detail. The proposed method reproduces the exact results k...