GROUND-STATE CORRELATIONS BEYOND RPA

An approach is proposed which includes ground-state correlations beyon d RPA. This is achieved by using a renormalized quasiboson approximati on with reference to the correlated ground state of the system, rather than to the uncorrelated Hartree-Fock one, and by expressing the part icle-particle and hole-hole pair operators in terms of the particle-ho le ones. The set of the so-obtained nonlinear equations for the one-ph onon energy and amplitudes are first solved within the Lipkin-Meshkov- Glick model and the results are compared with those of previous approa ches as well as with the exact ones. Applications to realistic nuclei, starting from fully self-consistent HF + RPA calculations with a Skyr me force are also presented.