A rich man's derivation of scaling laws for the Kondo model

TL;DR

This paper derives the Kondo model's scaling laws using a functional renormalization group approach, offering a more comprehensive method that extends beyond traditional techniques to include strong coupling regimes.

Contribution

It introduces a functional renormalization group framework for deriving Kondo model scaling laws, surpassing the limitations of the traditional poor man's scaling approach.

Findings

Derivation of one-loop scaling equations within the FRG framework.

Demonstration that the method extends to strong coupling regimes.

Comparison showing advantages over traditional poor man's scaling.

Abstract

We show how the one-loop "poor man's scaling" equations for the Kondo model with arbitrary impurity spin can be obtained within the framework of the functional renormalization group approach for quantum spin systems recently developed by Krieg and Kopietz [arXiv:1807.02524]. We argue that our method supersedes the "poor man's scaling" approach and can also be used to study the strong coupling regime of the Kondo model.