Journal of Statistical Physics, Vol. 38, Nos. 1/2, 1985. p. 125-147.
In this work we give the exact solution of the model describing the scattering of conduction electrons by an impurity in the orbital singlet state (so-called n-channel Kondo problem). Depending on the relation between the impurity spin S and the number of electron scattering channels n, the model behaves differently at low energies. At n \< 2S the effective charge increases to infinity at low energies, whereas at n > 2S it tends to a finite fixed point. The model under study is the first example of the one-dimensional quantum field theory exhibiting
scaling behavior.