Saturation in Nuclear Matter: a New Perspective

Abstract

The nucleon self-energy in nuclear matter is calculated including particle- particle (pp) as well as hole-hole (hh) ladder contributions. It is shown that a proper treatment of the analytic structure of the ladder summed effective interaction Γ^B, requires the numerical use of dispersion relations in order to calculate the self-energy correctly. These results in principle allow a fully self-consistent treatment of the ladder equation and the Dyson equation for the single-particle propagator including the full energy dependence of the self-energy. As a first step towards such a complete solution the single-particle energy is calculated self-consistently from the real on-shell self-energy which contains both forward(pp)- and backward(hh)- going terms. The contribution of the hh contribution to the sp energy is repulsive for all momenta and larger than the increased attraction from the pp contribution leading to less binding energy. This effect increases strongly with density and therefore leads to a saturation mechanism which has not been identified previously. First results for the v₂ homework potential are discussed.

This reseach was supported in part by NATO under Grant No. RG.85/0684 and by the Condensed Matter Theory Program of the Division of Materials Research of the U.S National Science foundation under Grant No. DMR-8519077 (at Washington University).