Correlated Ground State and Giant Resonances Built on It

It is demonstrated that a slight modification of the time-dependent density-matrix theory (TDDM) which was originally formulated to describe nuclear dynamics in terms of a mean field and two-body correlations provides us with a method for obtaining a correlated ground state. In the modified TDDM the residual interaction is gradually turned on starting with the Hartree-Fock (HF) ground state. The ground state correlations and El and E2 giant resonances in 40Ca are studied using the modified TDDM. Special emphasis is given to the comparison of the energy spectra of the giant resonances built on the correlated ground state with those built on the HF ground state. It is found that spurious components seen in the E2 giant resonance built on the HF ground state can be eliminated through a consistent treatment of the ground state. Ground state correlations and giant resonances in 220 are also studied in the same framework to elucidate the role of two-body correlations in such unstable nuclei. It is found that the effects of two-body correlations are not so important in such a neutron rich nucleus as in the closed-shell nuclei. In order to incorporate the effects of two-body correlations into the time-depend