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Although ab initio calculations of relativistic Brueckner theory lead to large scalar isovector fields in nuclear matter, at present, successful versions of covariant density functional theory neglect the interactions in this Channel. A new high-precision density functional DD-MEδ is presented which includes four mesons, &sigmal, ω, δ, and ρ, with density-dependent meson-nucleon couplings. It is based to a large extent on microscopic ab initio calculations in nuclear matter. Only four of its parameters are determined by adjusting to binding energies and Charge radii of finite nuclei. The other parameters, in particular the density dependence of the meson-nucleon vertices, are adjusted to nonrelativistic and relativistic Brueckner calculations of Symmetrie and asymmetric nuclear matter. The isovector effective mass Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. derived from relativistic Brueckner theory is used to determine the coupling strength of the δ meson and its density dependence. [ABSTRACT FROM AUTHOR]

Exotic and drip-line nuclei as well as nuclei immersed in a low-density gas of neutrons in the inner crust of neutron stars are systematically investigated with respect to their neutron pairing properties. This is done using Skyrme density-functional and different pairing forces such as a density-dependent contact interaction and a separable form of a finite-range Gogny interaction. Hartree-Fock-Bogoliubov (HFB) and Bardeen-Cooper-Schrieffer (BCS) theories are compared. It is found that neutron pairing is reduced towards the drip line while overcast by strong shell effects. Furthermore, resonances in the continuum can have an important effect counterbalancing the tendency of reduction and leading to a persistence of pairing at the drip line. It is also shown that in these systems the difference between HFB and BCS approaches can be quantitatively large. [ABSTRACT FROM AUTHOR]