2,778 research outputs found
Remarks on the use of projected densities in the density dependent part of Skyrme or Gogny functionals
I discuss the inadequacy of the "projected density" prescription to be used
in density dependent forces/functionals when calculations beyond mean field are
pursued. The case of calculations aimed at the symmetry restoration of mean
fields obtained with effective realistic forces of the Skyrme or Gogny type is
considered in detail. It is shown that at least for the restoration of spatial
symmetries like rotations, translations or parity the above prescription yields
catastrophic results for the energy that drive the intrinsic wave function to
configurations with infinite deformation, preventing thereby its use both in
projection after and before variation.Comment: To be published as a contribution to J. Phys G, Special Issue, Focus
Section: Open Problems in Nuclear Structur
Dual characterization of critical fluctuations: Density functional theory & nonlinear dynamics close to a tangent bifurcation
We improve on the description of the relationship that exists between
critical clusters in thermal systems and intermittency near the onset of chaos
in low-dimensional systems. We make use of the statistical-mechanical language
of inhomogeneous systems and of the renormalization group (RG) method in
nonlinear dynamics to provide a more accurate, formal, approach to the subject.
The description of this remarkable correspondence encompasses, on the one hand,
the density functional formalism, where classical and quantum mechanical
analogues match the procedure for one-dimensional clusters, and, on the other,
the RG fixed-point map of functional compositions that captures the essential
dynamical behavior. We provide details of how the above-referred theoretical
approaches interrelate and discuss the implications of the correspondence
between the high-dimensional (degrees of freedom) phenomenon and
low-dimensional dynamics.Comment: 8 figure
Cluster radioactivity of Th isotopes in the mean-field HFB theory
Cluster radioactivity is described as a very mass asymmetric fission process.
The reflection symmetry breaking octupole moment has been used in a mean field
HFB theory as leading coordinate instead of the quadrupole moment usually used
in standard fission calculations. The procedure has been applied to the study
of the ``very mass asymmetric fission barrier'' of several even-even Thorium
isotopes. The masses of the emitted clusters as well as the corresponding
half-lives have been evaluated on those cases where experimental data exist.Comment: Contribution to XIV Nuclear Physics Workshop at Kazimierz Dolny,
Poland, Sept. 26-29, 200
Microscopic description of fission in neutron-rich plutonium isotopes with the Gogny-D1M energy density functional
The most recent parametrization D1M of the Gogny energy density functional is
used to describe fission in the isotopes Pu. We resort to the
methodology introduced in our previous studies [Phys. Rev. C \textbf{88},
054325 (2013) and Phys. Rev. C \textbf {89}, 054310 (2014)] to compute the
fission paths, collective masses and zero point quantum corrections within the
Hartree-Fock-Bogoliubov framework. The systematics of the spontaneous fission
half-lives t, masses and charges of the fragments in Plutonium isotopes
is analyzed and compared with available experimental data. We also pay
attention to isomeric states, the deformation properties of the fragments as
well as to the competition between the spontaneous fission and -decay
modes. The impact of pairing correlations on the predicted t values is
demonstrated with the help of calculations for Pu in which the
pairing strengths of the Gogny-D1M energy density functional are modified by 5
and 10 , respectively. We further validate the use of the D1M
parametrization through the discussion of the half-lives in Fm. Our
calculations corroborate that, though the uncertainties in the absolute values
of physical observables are large, the Gogny-D1M Hartree-Fock-Bogoliubov
framework still reproduces the trends with mass and/or neutron numbers and
therefore represents a reasonable starting point to describe fission in heavy
nuclear systems from a microscopic point of view.Comment: 14 pages, 11 figures. arXiv admin note: text overlap with
arXiv:1312.722
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