Numerical Renormalization Group Study of the O(3)-symmetric Anderson Model

TL;DR

This paper employs the numerical renormalization group to analyze the O(3)-symmetric Anderson model, revealing a non-Fermi liquid fixed point and its instability under channel anisotropy, thus advancing understanding of complex impurity models.

Contribution

It provides a detailed NRG analysis of the O(3)-symmetric Anderson model, highlighting the existence and instability of non-Fermi liquid fixed points.

Findings

Identified a non-Fermi liquid fixed point in the isotropic case.

Showed the fixed point is unstable with respect to channel anisotropy.

Mapped the thermodynamic behavior across the model's parameter space.

Abstract

We use the numerical renormalization group method to study the O(3)-symmetric version of the impurity Anderson model of Coleman and Schofield. This model is of general interest because it displays both Fermi liquid and non-Fermi liquid behaviour, and in the large $U$ limit can be related to the compactified two channel Kondo model of Coleman, Ioffe and Tsvelik. We calculate the thermodynamics for a parameter range which covers the full range of behaviour of the model. We find a non-Fermi liquid fixed point in the isotropic case which is unstable with respect to channel anisotropy.