One-and-a-half-channel Kondo model and its family of non-Fermi liquids

TL;DR

This paper introduces the one-and-a-half-channel Kondo (1.5CK) model, a simplified non-Fermi liquid impurity model with odd electron species screening, and analyzes its properties using representation theory and numerical methods.

Contribution

It constructs and analyzes the 1.5CK model, a novel non-Fermi liquid impurity model with fewer degrees of freedom than traditional multi-channel models.

Findings

The 1.5CK model exhibits non-Fermi liquid behavior.

Derived the model for a spin-half impurity in cubic crystal fields.

Solved the model using numerical renormalization group techniques.

Abstract

I construct non-Fermi liquid (NFL) quantum impurity models that are similar to the overscreened multi-channel Kondo models with the difference that an odd number of electron species screen the impurity. The simplest of them, named sesqui-channel (i.e. one-and-a-half-channel) Kondo (1.5CK) model, has less degrees of freedom and is simpler than the two-channel Kondo model, and yet it exhibits NFL physics. Using representation theory I derive the 1.5CK model for a spin-half impurity surrounded with electrons in cubic crystal field and solve it with the numerical renormalization group.