2,287 research outputs found
Non-locality in the nucleon-nucleon interaction and nuclear matter saturation
We study the possible relationship between the saturation properties of
nuclear matter and the inclusion of non-locality in the nucleon-nucleon
interaction. To this purpose we compute the saturation curve of nuclear matter
within the Bethe-Brueckner-Goldstone theory using a recently proposed realistic
non-local potential, and compare it with the corresponding curves obtained with
a purely local realistic interaction (Argonne v) and the most recent
version of the one-boson exchange potential (CD Bonn). We find that the
inclusion of non-locality in the two-nucleon bare interaction strongly affects
saturation, but it is unable to provide a consistent description of few-body
nuclear systems and nuclear matter.Comment: 9 pages, 8 figures; v2: introduction extended, references added,
discussion of fig.8 reformulated; to be published in Phys. Rev.
Hybrid protoneutron stars with the MIT bag model
We study the hadron-quark phase transition in the interior of protoneutron
stars. For the hadronic sector, we use a microscopic equation of state
involving nucleons and hyperons derived within the finite-temperature
Brueckner-Bethe-Goldstone many-body theory, with realistic two-body and
three-body forces. For the description of quark matter, we employ the MIT bag
model both with a constant and a density-dependent bag parameter. We calculate
the structure of protostars with the equation of state comprising both phases
and find maximum masses below 1.6 solar masses. Metastable heavy hybrid
protostars are not found.Comment: 12 pages, 9 figures submitted to Phys. Rev.
Strange hadronic stellar matter within the Brueckner-Bethe-Goldstone theory
In the framework of the non-relativistic Brueckner-Bethe-Goldstone theory, we
derive a microscopic equation of state for asymmetric and -stable matter
containing and hyperons. We mainly study the effects of
three-body forces (TBFs) among nucleons on the hyperon formation and the
equation of state (EoS). We find that, when TBFs are included, the stellar core
is almost equally populated by nucleons and hyperons. The resulting EoS, which
turns out to be extremely soft, has been used in order to calculate the static
structure of neutron stars. We obtain a value of the maximum mass of 1.26 solar
masses (1 solar mass ). Stellar rotations
increase this value by about 12%.Comment: 4 pages, Latex, 2 figures included. To appear in the Proceedings of
'' Bologna 2000 - Structure of the Nucleus at the Dawn of the Century'', May
29- June 3, 2000, Bologna, Ital
Structure of hybrid protoneutron stars within the Nambu--Jona-Lasinio model
We investigate the structure of protoneutron stars (PNS) formed by hadronic
and quark matter in -equilibrium described by appropriate equations of
state (EOS). For the hadronic matter, we use a finite temperature EOS based on
the Brueckner-Bethe-Goldstone many-body theory, with realistic two- and
three-body forces. For the quark sector, we employ the Nambu--Jona-Lasinio
model. We find that the maximum allowed masses are comprised in a narrow range
around 1.8 solar masses, with a slight dependence on the temperature.
Metastable hybrid protoneutron stars are not found.Comment: 7 pages, 6 figures, revised version accepted for publication in Phys.
Rev.
Chaos vs. Linear Instability in the Vlasov Equation: A Fractal Analysis Characterization
In this work we discuss the most recent results concerning the Vlasov
dynamics inside the spinodal region. The chaotic behaviour which follows an
initial regular evolution is characterized through the calculation of the
fractal dimension of the distribution of the final modes excited. The ambiguous
role of the largest Lyapunov exponent for unstable systems is also critically
reviewed.Comment: 10 pages, RevTeX, 4 figures not included but available upon reques
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