317 research outputs found
Self-consistent Theory of Finite Fermi Systems vs Skyrme-Hartree-Fock method. Spherical nuclei
Recent results of the Fayans energy density functional (EDF) for spherical
nuclei are reviewed. A comparison is made with predictions of several Skyrme
EDFs. The charge radii and characteristics of the first 2^+ excitations in
semi-magic nuclei are briefly discussed. The single-particle spectra of doubly
magic nuclei are considered in more detail. The phonon-particle coupling
effects are analyzed including the so-called tadpole term.Comment: 6 pages, 7 figures, to appear in the proceedings of the International
Conference "Nuclear Structure and Relaited Topics", July 14 - July 18, 2015,
Dubna, Russia. arXiv admin note: text overlap with arXiv:1401.131
Microscopic origin of pairing
A brief review of recent progress in the ab intio theory of nuclear pairing
is given. Nowdays several successful solutions of the ab intio BCS theory gap
equation were published which show that it is a promising first step in the
problem. However, the role of many-body correlations that go beyond the BCS
scheme remains uncertain and requires further investigations. As an
alternative, the semi-microscopic model is discussed in which the effective
pairing interaction calculated from the first principles is supplemented with a
small phenomenological addendum containing one phenomenological parameter
universal for all medium and heavy atomic nuclei.Comment: Contribution to the Volume 50 years of Nuclear BCS edited by World
Scientifi
Particle-phonon coupling effects within theory of finite Fermi systems
Recent results of the study of the particle-phonon coupling (PC) effects in
odd magic and semi-magic nuclei within the self-consistent theory of finite
Fermi systems are reviewed. In addition to the usual pole diagrams, the
non-pole ones are considered. Their contributions are often of a crucial
importance. PC corrections to the single-particle energies for Ca and
Pb are presented. The quadrupole moments of odd In and Sb isotopes, the
odd-proton neighbors of even Sn isotopes, are presented also with accounting
for the PC corrections. At last, recently announced problem of extremely high
values charge radii of heavy Ca isotopes is solved in terms of a consistent
consideration of the PC effects. In all the cases, rather good description of
the data is obtained.Comment: 10 pages, 6 figures, to appear in the proceedings of the Fifth
Conference on NUCLEI and MESOSCOPIC Physics (NMP17), March 6-10, 2017; East
Lansing, Michigan, US
Device prepares aluminum surfaces for welding
Dry machining technique removes original surfaces to obtain contamination free welding surface. Device straddles edge being prepared and aligns with existing edges and adjacent surfaces of workpiece while sensing device regulates cut depth. Description of prototype is given
An ab initio theory of double odd-even mass differences in nuclei
Two aspects of the problem of evaluating double odd-even mass differences D_2
in semi-magic nuclei are studied related to existence of two components with
different properties, a superfluid nuclear subsystem and a non-superfluid one.
For the superfluid subsystem, the difference D_2 is approximately equal to
2\Delta, the gap \Delta being the solution of the gap equation. For the
non-superfluid subsystem, D_2 is found by solving the equation for two-particle
Green function for normal systems. Both equations under consideration contain
the same effective pairing interaction. For the latter, the semi-microscopic
model is used in which the main term calculated from the first principles is
supplemented with a small phenomenological addendum containing one
phenomenological parameter supposed to be universal for all medium and heavy
atomic nuclei.Comment: 7 pages, 10 figures, Report at Nuclear Structure and Related Topics,
Dubna, Russia, July 2 - July 7, 201
Magnetic moments of odd-odd spherical nuclei
Magnetic moments of more than one hundred odd-odd spherical nuclei in ground
and excited states are calculated within the self-consistent TFFS based on the
EDF method by Fayans {\it et al}. We limit ourselves to nuclei with a neutron
and a proton particle (hole) added to the magic or semimagic core. A simple
model of no interaction between the odd nucleons is used. In most the cases we
analyzed, a good agreement with the experimental data is obtained. Several
cases are considered where this simple model does not work and it is necessary
to go beyond. The unknown values of magnetic moments of many unstable odd and
odd-odd nuclei are predicted including sixty values for excited odd-odd nuclei.Comment: 10 page
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