Application of tridiagonalization to the many-body problem. II. Finite<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>T</mml:mi></mml:math>

Abstract

In a previous paper of the same title, we obtained the ground-state energy of a magnetic (Wolff-model) impurity in a nonmagnetic metal. In the present Brief Report, we calculate the impurity's contribution to the density of states and heat capacity of the metal at low temperatures. Here, the Lancz\"os reduction ("tridiagonalization") converges less rapidly, so that our results are of qualitative merit only. Nevertheless, we confirm the validity of perturbation theory in the weak-coupling regime, and find, at strong coupling, that the interaction introduces an extra fraction $\frac{2}{N}$ of states at the Fermi level.