Ground state correlations and anharmonicity of vibrations

A consistent treatment of the ground state correlations beyond the random phase approximation including their influence on the pairing and phonon-phonon coupling in nuclei is presented. A new general system of nonlinear equations for the quasiparticle phonon model (QPM) is derived. It is shown that this system contains as a particular case all equations derived for the QPM early. New additional Pauli principle corrections resulting in the anharmonical shifts of energies of the two-phonon configurations are found. A correspondence between the generalized QPM equations and the nuclear field theory is discussed.