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We analyze the influence of the density dependence of the symmetry energy on the average excitation energy of the isoscalar giant monopole resonance (GMR) in stable and exotic neutron-rich nuclei by applying the relativistic extended Thomas-Fermi method in scaling and constrained calculations. For the effective nuclear interaction, we employ the relativistic mean field model supplemented by an isoscalar-isovector meson coupling that allows one to modify the density dependence of the symmetry energy without compromising the success of the model for binding energies and charge radii. The semiclassical estimates of the average energy of the GMR are known to be in good agreement with the results obtained in full RPA calculations. The present analysis is performed along the Pb and Zr isotopic chains. In the scaling calculations, the excitation energy is larger when the symmetry energy is softer. The same happens in the constrained calculations for nuclei with small and moderate neutron excess. However, for nuclei of large isospin the constrained excitation energy becomes smaller in models having a soft symmetry energy. This effect is mainly due to the presence of loosely-bound outer neutrons in these isotopes. A sharp increase of the estimated width of the resonance is found in largely neutron-rich isotopes, even for heavy nuclei, which is enhanced when the symmetry energy of the model is soft. The results indicate that at large neutron numbers the structure of the low-energy region of the GMR strength distribution changes considerably with the density dependence of the nuclear symmetry energy, which may be worthy of further characterization in RPA calculations of the response function., Comment: 25 pages, 5 figures; modifications in text

The extension of the density functional theory (DFT) to include pairing correlations without formal violation of the particle-number conservation condition is described. This version of the theory can be considered as a foundation of the application of existing DFT plus pairing approaches to atoms, molecules, ultracooled and magnetically trapped atomic Fermi gases, and atomic nuclei where the number of particles is exactly conserved. The connection with the Hartree-Fock-Bogoliubov theory is discussed. The method of the quasilocal reduction of the nonlocal theory is described. This quasilocal reduction allows to obtain equations of motion which are much more simple for the numerical solution than the equations corresponding to the nonlocal case., 17 pages, LaTeX

We show that in the search of a unified mean field description of finite nuclei and of nuclear and neutron matter even at high densities, the relativistic nuclear model derived from effective field theory and density functional theory methods constitutes a competitive framework. The model predicts a soft equation of state, owing to the additional meson interaction terms, consistently with the results of the microscopic Dirac-Brueckner-Hartree-Fock theory and recent experimental observations from heavy ion collisions. In finite systems, after inclusion of the pairing correlations, the model is able to describe both stable and exotic nuclei. We address two examples at the limits of the nuclear landscape. On the one hand, we analyze the giant halo effect and the isoscalar giant monopole resonance in very neutron-rich Zr isotopes. On the other hand, we discuss the structure of superheavy nuclei with double shell closures., 50 pages, 14 figures. Submitted to NOVA Science Publishers (NY) volume "Progress in Field Theory Research"

The quantum-kinetic energy of a finite number of trapped fermionic atoms provides a restoring force for shear motion due to a distortion of the momentum distribution. In analogy to the twist mode of nuclear physics it is proposed that counter-rotating the upper and lower hemisphere of a spherical atomic cloud yields a finite-frequency mode closely related to transverse zero-sound waves in bulk Fermi liquids., Comment: 4 pages, 1 table (using REVTeX)

The moment of inertia Q of a trapped superfluid gas of atomic Fermions (6Li) is calculated as a function of the temperature. At zero temperature the moment of inertia takes on the irrotational flow value. Only for T very close to Tc rigid rotation is attained. It is proposed that future measurements of the rotational energy will unambiguously reveal whether the system is in a superfluid state or not., Comment: 43 pages, 5 figures ; accepted in Phys. Rev. A

Surface and curvature properties of asymmetric nuclear matter are studied beyond the proton drip. Using the semiclassical extended Thomas-Fermi method, the calculations are performed in the non-relativistic and relativistic meson field theories (Skyrme forces and non linear sigma-omega parametrizations). First we discuss the bulk equilibrium between the nuclear and drip phases. Next we analyze the asymmetric surface as a function of the bulk neutron excess. We examine local quantities related to the density profiles and, for two definitions of the bulk reference energy, the surface and curvature energy coefficients. The calculation of the curvature energy is carefully treated. The sensitivity of the nuclear surface to the relativistic effects is investigated. Mass formulae useful for arbitray neutron excess are discussed, and their limit at small asymmetries is compared with the liquid droplet model mass formula., 47 pages, 17 figures in .tar.gz format Accepted for publishing in Nuclear Physics A