EMERY-KIVELSON SOLUTION OF THE 2-CHANNEL KONDO PROBLEM

We consider the two-channel Kondo model in the Emery-Kivelson approach, and calculate the total susceptibility enhancement due to the impurity chi(imp) = chi-chi(bulk). We find that chi(imp) exactly vanishes at the solvable point, in a completely analogous way to the singular part of the specific heat C(imp). A perturbative calculation around the solvable point yields the generic behavior chi(imp) approximately log(1/T), C(imp) approximately T logT and the known universal value of the Wilson ratio R(W) = 8/3. From this calculation, the Kondo temperature can be identified and is found to behave as the inverse square of the perturbation parameter. The small-field, zero-temperature behavior chi(imp) approximately log(1/h) is also recovered.