Long range tensor correlations in charge and parity projected fermionic molecular dynamics

Abstract

Within the framework of fermionic molecular dynamics a method is developed to better account for long-range tensor correlations in nuclei when working with a single Slater determinant. Single-particle states with mixed isospin and broken parity build up an intrinsic Slater determinant, which is then charge and parity projected. By minimizing the energy of this many-body state with respect to the parameters of the single-particle states and projecting afterward on angular momentum, ground-state energies are obtained that are systematically lower than corresponding Hartree-Fock results. The realistic Argonne V18 potential is used and short-range correlations are treated with the unitary correlation operator method. Comparison with exact few-body calculations shows that in $^{4}\mathrm{He}$ about one-fifth of the correlation energy from long-range correlations are accounted for. These correlations, which extend over the whole nucleus, are visualized with the isospin and spin-isospin density of the intrinsic state. The divergence of the spin-isospin density, the source for pion fields, turns out to be of dipole nature.