An effective dynamic interaction for the two-particle propagator

Abstract

In nuclear structure calculations the collective excitations of the core introduce dynamic effects in the interaction between particles. Under the restriction of including forward-going contributions only, it is shown that the two-particle propagator which yields the spectra and two-particle transfer strengths of nuclei with two nucleons outside a closed shell, can be written in a Dyson-like equation in which a two-particle self-energy or dynamic effective interactionΔ is introduced. An expression forΔ is given in terms of the irreducible vertex part of the Bethe-Salpeter equation and partial summations forΔ using phonon exchange interactions to represent the core-polarization diagrams, are discussed. The single-particle propagators are also dressed with phonon-exchange contributions.