956 research outputs found
Structure of exotic nuclei around double shell closures
In this paper, we first give a brief review of the theoretical framework for
microscopic shell-model calculations starting from the free nucleon-nucleon
potential. In this context, we discuss the use of the low-momentum
nucleon-nucleon interaction V-low-k in the derivation of the shell-model
effective interaction and emphasize its practical value as an alternative to
the Brueckner G-matrix method. Then, we present some results of our current
study of exotic nuclei around doubly magic 132Sn, which have been obtained
starting from the CD-Bonn potential renormalized by use of the V-low-k
approach. Attention is focused on the nuclei 134Te, 134Sn, and 136Te, in
particular on the latter which is a direct source of information on the
proton-neutron effective interaction in the 132Sn region. Comparison shows that
our results are in very good agreement with the available experimental data.Comment: 8 pages, 3 figures, to be published in Prog. Part. Nucl. Phy
Realistic shell-model calculations for neutron-rich calcium isotopes
We study the neutron-rich calcium isotopes performing shell-model
calculations with a realistic effective interaction. This is derived from the
CD-Bonn nucleon-nucleon potential renormalized by way of the V-low-k approach,
considering 48Ca as an inert core and including the neutron 0g9/2 orbital. We
compare our results with experiment and with the results of a previous study
where 40Ca was assumed as a closed core and the standard 1p0f model space was
employed. The calculated spectroscopic properties are in both cases in very
good agreement with the available experimental data and enable a discussion on
the role of the g9/2 single-particle state in the heavy-mass Ca isotopes.Comment: 7 pages, 1 figure, 4 tables, talk presented at 10th International
Spring Seminar on Nuclear Physics "New Quests in Nuclear Structure", Vietri
sul Mare, may 21-25, 2010. To be published on Journal of Physics Conference
Serie
Self-Consistent Nuclear Shell-Model Calculation Starting from a Realistic NN Potential
First self-consistent realistic shell-model calculation for the light p-shell
nuclei is performed, starting from the high-precision nucleon-nucleon (NN)
CD-Bonn potential. This realistic potential is renormalized deriving a
low-momentum NN potential V-low-k that preserves exactly the two-nucleon
low-energy physics. This V-low-k is suitable to derive a self-consistent
Hartree-Fock basis that is employed to derive both effective single-particle
energies and residual two-body matrix elements for the shell-model hamiltonian.
Results obtained show the reliability of such a fundamental microscopic
approach.Comment: 4 pages, 1 figure, 8 tables, to be published on Physics Letters
Realistic Shell-Model Calculations for Nuclei in the Region of Shell Closures off Stability
We have performed realistic shell-model calculations for nuclei around doubly
magic 100Sn and 132Sn using an effective interaction derived from the Bonn A
nucleon-nucleon potential. The results are in remarkably good agreement with
the experimental data showing the ability of our effective interaction to
provide an accurate description of nuclear structure properties.Comment: 6 pages, 6 figures, Proceedings of the SNEC98 Conference, to be
published on Nuovo Cimento
Observer design for piecewise smooth and switched systems via contraction theory
The aim of this paper is to present the application of an approach to study
contraction theory recently developed for piecewise smooth and switched
systems. The approach that can be used to analyze incremental stability
properties of so-called Filippov systems (or variable structure systems) is
based on the use of regularization, a procedure to make the vector field of
interest differentiable before analyzing its properties. We show that by using
this extension of contraction theory to nondifferentiable vector fields, it is
possible to design observers for a large class of piecewise smooth systems
using not only Euclidean norms, as also done in previous literature, but also
non-Euclidean norms. This allows greater flexibility in the design and
encompasses the case of both piecewise-linear and piecewise-smooth (nonlinear)
systems. The theoretical methodology is illustrated via a set of representative
examples.Comment: Preprint accepted to IFAC World Congress 201
g9/2 nuclei and neutron-proton interaction
We have performed shell-model calculations for nuclei below 100Sn, focusing
attention on the two N=Z nuclei 96Cd and 92Pd, the latter having been recently
the subject of great experimental and theoretical interest. We have considered
nuclei for which the 0g9/2 orbit plays a dominant role and employed a realistic
low-momentum two-body effective interaction derived from the CD-Bonn
nucleon-nucleon potential. This implies that no phenomenological input enters
our effective Hamiltonian. The calculated results for 92Pd are in very good
agreement with the available experimental data, which gives confidence in our
predictions for 96Cd. An analysis of the wave functions of both 96Cd and 92Pd
is performed to investigate the role of the isoscalar spin-aligned coupling.Comment: 7 pages, 6 figures, 4 tables, to be published in Physical Review
Proton-neutron multiplets in exotic 134Sb: testing the shell-model effective interaction
The experimental level structure of 134Sb is compared with the results of a
shell-model calculation in which the two-body matrix elements of the effective
interaction have been derived from the CD-Bonn nucleon-nucleon potential. The
experimental data, including the very low-lying first-excited 1- state, are
remarkably well reproduced by the theory. The results of this paper complement
those of our previous studies on 135Sb and 134Sn, showing that our effective
interaction is well suited to describe 132Sn neighbors beyond N=82. The various
terms which contribute to the matrix elements of the proton-neutron effective
interaction are examined and their relative importance is evidenced.Comment: 4 pages, 3 figures, published on Physical Review
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