6,799 research outputs found
Electrically charged pulsars
n the present work we investigate one possible variation on the usual
electrically neutral pulsars: the inclusion of electric charge. We study the
effect of electric charge in pulsars assuming that the charge distribution is
proportional to the energy density. All calculations were performed for zero
temperature and fixed entropy equations of state
Generalized Born-Infeld-like models for kinks and branes
In this work we deal with a non-canonical scalar field in the two-dimensional
spacetime. We search for a generalized model that is twin of the standard
model, supporting the same defect structure with the same energy density. We
also study the stability of the defect solution under small fluctuations, which
is governed by a Sturm-Liouville equation, and show how to make it stable. The
model is then modified and used in the five-dimensional spacetime to construct
a thick brane that engenders the first order framework and preserves the
twinlike behavior, under tensorial fluctuations of the metric in its
gravitational sector.Comment: 6 pages; v3, to appear in EP
Nuclear Matter Properties in Derivative Coupling Models Beyond Mean - Field Approximation
The structure of infinite nuclear matter is studied with two of the Zimanyi -
Moszkowski (ZM) models in the framework of a relativistic approximation which
takes into account Hartree terms and beyond and is compared with the results
which come out of the relativistic Hartree - Fock approach in the linear
Walecka model. The simple treatment applied to these models can be used in
substitution to the more complicated Dirac - Brueckner - Hartree - Fock method
to perform future calculations in finite nuclei.Comment: 11 pages including 1 table, 1 figure (available upon request
Particle yields in heavy ion collisions and the influence of strong magnetic fields
It is expected that the magnetic field in the surface of magnetars do not
exceed G. However, in heavy ion collisions, this value is expected to
be much higher. We investigate the effects of a magnetic fields varying from
, to G in strange matter (composed of , and
quarks). We model matter as a free gas of baryons and mesons under the
influence of an external magnetic field. We study the effects of such strong
fields through a fit to some data sets of the STAR experiment. For
this purpose we solve the Dirac, Rarita-Schwinger, Klein-Gordon and Proca
equations subject to magnetic fields in order to obtain the energy expressions
and the degeneracy for spin 1/2, spin 3/2, spin 0 and spin 1 particles,
respectively. Our results show that a field of the order of G
produces an improved fitting to the experimental data as compared to the
calculations without magnetic field.Comment: 20 pages, 16 figures, 4 table
Exact solutions, energy and charge of stable Q-balls
In this work we deal with nontopological solutions of the Q-ball type in two
spacetime dimensions. We study models of current interest, described by a
Higgs-like and other, similar potentials which unveil the presence of exact
solutions. We use the analytic results to investigate how to control the energy
and charge to make the Q-balls stable.Comment: 11 pages, 18 figures; v2, title changed, reference adde
Stable finite energy global vortices and asymptotic freedom
This work deals with global vortices in the three-dimensional spacetime. We
study the case of a simple model with symmetry and find a way to
describe stable, finite energy global vortices. The price we pay to stabilize
the solution is the presence of scale invariance, but we have found a way to
trade it with an electric charge in a medium with generalized permittivity,
which is further used to capture the basic feature of asymptotic freedom.Comment: 6 pages, 3 figures. To appear in EP
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