Masao Nomura; Reduction Formulae for the Seniority Diagonal Matrix Element of a Two-Body Interaction in a Boson System, Progress of Theoretical Physics, Volume
The seniority scheme introduced by Racah is generalized in the case of degenerate levels. Many formulae for the pure configuration j n are modified in order to calculate matrix elements in this generalized seniority scheme. It is especially the most interesting result that the diagonal matrix element of two-body operators between the states with the same seniority v can be expressed in terms of the matrix elements in the v -particle system. This result, of course, holds in the case of the pure configuration.