Covariant ab initio Approach to Nuclear Matter, Nuclei and Neutron Stars

Nuclear matter and finite nuclei at extreme isospin are studied the DDRH field theory. In-medium interactions in nuclear and hypernuclear matter are described with density dependent meson-baryon vertex functionals, derived from Dirac-Brueckner theory. Relativistic mean-field results are presented ranging from nuclear matter over isotopic chains of nuclei to neutron stars. Dynamical correlations from pairing interactions and core polarization are found to increase strongly when approaching the driplines. Above particle threshold core polarization gives rise to narrow Fano Resonances as new mode of continuum excitation. This is accompanied by a strong reduction of mean-field configurations, as indeed observed in recent experiments. Anharmonicities in dipole excitations are investigated along isotopic chains including up to three phonon admixtures and using microscopic HFB quasiparticle input. Pygmy dipole resonances are found to provide a clear signature for neutron skins.