Approximate projection of physical states in the quasiparticle description of nuclear collective motion

A new method of treating the problem of number nonconservation in quasiparticle descriptions of nuclear collective motion is proposed. In this method, successive orders of approximate number projection are performed directly on the quasiparticle states in question. Even in the lowest orders of approximation, the number-projected states thus obtained turn out to be quite accurate in producing physical quantities. Furthermore, by incorporating the number projections in the shell-model single-particle operators, we obtain a quantized version of the Bogoliubov transformation which can greatly simplify the task of restoring number conservation for various calculations using quasi-particle representations. (orig.)