Scaling solution of the overscreened multichannel Kondo model

Abstract

In the Kondo problem the overscreened multichannel model is the only one that can be assessed perturbatively. However, until now there are still problems remaining in studies by means of a perturbative renormalization group due to the absence of a proper treatment on the constraint of the pseudofermion. In this paper we try to settle these problems. We studied the general overscreened multichannel Kondo problem by means of a field-theory renormalization group with the technique of treating the pseudofermion constraint as developed recently. We calculated the critical exponent, specific heat, magnetic susceptibility, residue entropy, and Wilson ratio for the overscreened multichannel Kondo model. From these results we conclude that all overscreened multichannel Kondo models with the same channel number $K$ but different $S$ have the same fixed point properties. Therefore, they belong to the same universal class, which agrees with the result obtained by Bethe ansatz and conformal field theory.