Dissolution of shell structures and the polarizability of dripline nuclei

Abstract

Nuclear matter and finite nuclei at extreme isospin are studied within the microscopical Giessen energy density functional (GEDF). The structure of the GEDF is discussed. Quasiparticle wave equations and the residual interactions are derived by variational methods. Applications to nuclear ground and excited states by HFB and QRPA methods and extensions to multi-phonon theory are indicated. Pairing effects are described by the Gorkov coupled channels approach by which wave function effects are accounted for. Pairing self-energies for continuum states and the resulting additional scattering phase shifts are introduced. It is shown that pairing and polarization self-energies can induce narrow resonances in continuum spectra. Dipole and quadrupole response functions and polarizabilities are discussed as signatures for halo and skin dynamics in lithium and in carbon isotopes. The recently established new pygmy dipole (PDR) and quadrupole (PQR) modes are considered as signatures for nuclear skin dynamics. Their importance for astrophysical reaction rates and stellar nucleo-synthesis is investigated.