Conformal Field Theory Approach to Quantum Impurity Problems

TL;DR

This paper reviews a conformal field theory method for analyzing quantum impurity problems, highlighting its application to the overscreened Kondo problem and the relationship between fixed points in quantum spin chains.

Contribution

It introduces a new conformal field theory approach to quantum impurity problems and elucidates the connection between fixed points in spin chain models.

Findings

Analysis of overscreened Kondo problem results

Fixed points related by fusion in spin chain models

Demonstration of conformal field theory techniques effectiveness

Abstract

A brief review is given of a new method for studying the critical behavior of quantum impurity problems, based on conformal field theory techniques, which I developed with Andreas Ludwig. Some results on the overscreened Kondo problem are reviewed. It is shown that the simple open and periodic fixed points, which occur in quantum spin chain impurity models, are related to each other by fusion.