Numerical renormalization group study of two-level Kondo effect: Discovery of new fixed point

TL;DR

This paper uses the numerical renormalization group method to discover a new weak-coupling fixed point in the two-level Kondo effect model, expanding understanding beyond previous strong-coupling solutions.

Contribution

It identifies a novel weak-coupling fixed point in the two-level Kondo model, previously unrecognized in earlier renormalization group analyses.

Findings

Discovery of a new weak-coupling fixed point

Existence of fixed point beyond the known strong-coupling solution

Enhanced understanding of the two-level Kondo effect

Abstract

The model of two-level Kondo effect is studied by the Wilson numerical renormalization group method. It is shown that there exist a new type of weak-coupling fixed point other than the strong-coupling fixed point found by Vladar and Zawadowski two decades ago by means of the one-loop and two-loop renormalization group methods.