80 research outputs found
Exact and Nearly Exact Pairing Treatment for Large Scale Calculations
International audienceIn this article we present an analysis of the practical applicability of the earlier introduced PSY-MB method in solving the nuclear pairing Hamiltonian. In particular, we illustrate the convergence properties of the ground-state correlation energy, as well as the first excitation energy, in the case of the so-called picket-fence model where 32 particles are distributed over 64 equispaced, doubly-degenerated levels. In order to illustrate the ability of the method, we compare the correlation energies of the ground-state to the exact solutions obtained with the Richardson formalism, as well as the BCS approach, in function of the increasing monopole pairing strength parameter
Particle-Particle Hole-Hole TDA – And Beyond – For The Nuclear Pairing Hamiltonian
International audienceA comparison of different seniority zero solutions to the picket-fence model for the nuclear pairing hamiltonian problem is performed. These solutions are calculated, in the normal regime, within the self-consistent Random Phase Approximation (SCRPA) and various simplifications of this formalism, and also with the Tamm-Dancoff approach in the particle-particle-hole-hole channel (pphh-TDA). The latter formalism represents a first approximation to the earlier developped so-called P-Symmetric Many-Body method (PSY-MB). In the superfluid regime, the solutions are compared with the BCS results. By comparing the results with the exact ones, obtained by the Richardson method, it is shown that the PSY-MB method provides a powerful tool in solving the problem with good accuracy both in the normal and the superfluid regime, for single-particle space sizes adapted to typical nuclear structure calculations
Superdeformed bands in and neighboring nuclei predicted within the Hartree-Fock method
Superdeformed configurations in 32S, and in neighboring nuclei 33S, 31S, 33Cl, and 31P, are determined within the Hartree-Fock approach with the Skyrme interaction. Energies, angular momenta, quadrupole moments, particle-emission Q-values, and relative alignments and quadrupole moments are calculated for a number of superdeformed rotational bands in these nuclei. A new mechanism implying an existence of signature-separated rotational bands, distinct from the well-known signature-split bands, is discussed and associated with the time-odd channels of effective interactions
Notes
Notes by Richard A. Molique, F. Louis Fautsch, John A. Berry, Joseph A. McCabe, Stephen P. Banas, Robert Devine, John J. Locher, and J. S. Montedonico
Characteristic Feature of Self-Consistent Mean-Field in Level Crossing Region
A shape change of the self-consistent mean-field induced by a configuration
change is discussed within the conventional constrained Hartree-Fock (CHF)
theory. It is stressed that a single-particle level crossing dynamics should be
treated carefully, because the shape of the mean-field in such a finite
many-body system as the nucleus strongly changes depending on its
configuration. This situation is clearly shown by applying an adiabatic
assumption, where the most energetically favorable single-particle states are
assumed to be occupied. The excited HF states and the continuously-connected
potential energy curves are given by applying the configuration dictated CHF
method. The effect of pairing correlation is discussed in the level crossing
region. Triaxial deformed results in our Hartree-Fock-Bogoliubov (HFB)
calculation with Gogny force nicely reproduce the available experimental data
of Ge isotopes. From our numerical calculation, it is concluded that the CHFB
state is more fragile than the CHF state in the level crossing region.Comment: 25 pages, 6 figures and 2 table
Superdeformed bands in neutron-rich Sulfur isotopes suggested by cranked Skyrme-Hartree-Fock calculations
On the basis of the cranked Skyrme-Hartree-Fock calculations in the
three-dimensional coordinate-mesh representation, we suggest that, in addition
to the well-known candidate 32S, the neutron-rich nucleus 36S and the drip-line
nuclei,48S and 50S, are also good candidates for finding superdeformed
rotational bands in Sulfur isotopes. Calculated density distributions for the
superdeformed states in 48S and 50S exhibit superdeformed neutron skinsComment: 18 pages including 10 ps figure
- …