A Unified Description of Pairing Correlation in Nuclei

By the method of linearized equations of motion for the fundamental pair operators, the pairing system in nuclei is treated unifiedly for both the normal and the super region. Any "free" vacuum is not assumed, which enables us the number conserving treatment. With the generalized definition of the gap energy d and the chemical potential A., a new gap equation and the number conserving random phase approximation are derived. The normalization of ampli· tudes is determined by energy-weighted sum rules. Applications are made. to the degenerate case and the two-shell case. The agreement between the theory and the exact solution is good for any interaction strength. An essential point of our theory is that it makes possible a description of the so-called transitional region with slight modifications of the conventional theory.