Abstract
The authors determine the one-particle and two-particle spectra of the degenerate Hubbard model with partially filled bands within the self-consistent T-matrix approximation and the ladder approximation, respectively. They have found that the effect of self-consistency is important even for metals with a small particle concentration, e.g., Ni. The results are compared with the theory of Treglia et al. (1980, 1981) as well as with the theory of Cini (1976, 1979), which represents basically the non-self-consistent version of the approach.