Renormalization Group Approach to Spectral Properties of the Two-Channel Anderson Impurity Model

TL;DR

This paper analyzes the spectral properties of the two-channel Anderson impurity model using a renormalization group approach, revealing non-Fermi liquid behavior and universal features in the impurity Green function and susceptibilities.

Contribution

It provides an exact expression for the impurity Green function's self-energy and characterizes the non-Fermi liquid spectral features of the two-channel Anderson model.

Findings

Self-energy's imaginary part scales as √|ω/T_K| at T→0

Resonance pinned at 1/(2πΔ) at ω=0

Dynamical susceptibilities governed by T_K and T_h, approaching constants as ω→0

Abstract

The impurity Green function and dynamical susceptibilties for the two-channel Anderson impurity model are calculated. An exact expression for the self-energy of the impurity Green function is derived. The imaginary part of the self-energy scales as $\sqrt{|\w/T_K|}$ for $T\to 0$ serving as a hallmark for non-Fermi behavior. The many-body resonance is pinned to a universal value $1/(2\pi\Delta)$ at $\w=0$. Its shape becomes increasingly more symmetric for the Kondo-regimes of the model. The dynamical susceptibilities are governed by two energy scales $T_K$ and $T_h$ and approach a constant value for $\w\to 0$, whereas relation $\chi''(\w)\propto \w$ holds for the single channel model.