Local energy density functional and density-dependent pairing in nuclear systems

An approach based on the local energy density functional method for describing the ground-state properties of superfluid nuclei is presented. A generalized variational principle is formulated which corresponds, in the weak pairing approximation, to a full treatment of the Hartree-Fock-Bogoliubov problem with an effective contact pairing interaction. The Gor'kov equations for generalized Green's functions are treated exactly in the coordinate-space representation. The method is used to calculate the differential observables including odd-even mass differences and odd-even effects in charge radii which turn out to be very sensitive to the density dependence of the effective pairing force. A better knowledge of this density dependence allows one to make predictions for the pairing gap at the Fermi surface as a function of nuclear matter density. (C) 1998 American Institute of Physics. [S0021-3640(98)00216-3].