10,874 research outputs found
Quark matter equation of state and stellar properties
In this paper we study strange matter by investigating the stability window
within the QMDD model at zero temperature and check that it can explain the
very massive pulsar recently detected. We compare our results with the ones
obtained from the MIT bag model and see that the QMDD model can explain larger
masses, due to the stiffening of the equation of state
Trapping of Spin-0 fields on tube-like topological defects
We have considered the localization of resonant bosonic states described by a
scalar field trapped in tube-like topological defects. The tubes are
formed by radial symmetric defects in dimensions, constructed with two
scalar fields and , and embedded in the dimensional
Minkowski spacetime. The general coupling between the topological defect and
the scalar field is given by the potential .
After a convenient decomposition of the field , we find that the
amplitudes of the radial modes satisfy Schr\"odinger-like equations whose
eigenvalues are the masses of the bosonic resonances. Specifically, we have
analyzed two simple couplings: the first one is for a
fourth-order potential and, the second one is a sixth-order interaction
characterized by % . In both cases the
Schr\"odinger-like equations are numerically solved with appropriated boundary
conditions. Several resonance peaks for both models are obtained and the
numerical analysis showed that the fourth-order potential generates more
resonances than the sixth-order one.Comment: 7 pages, 10 figures, matches version published in Physics Letters
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
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
Generalized scalar field models with the same energy density and linear stability
We study how the properties of a Lagrangian density for a single real scalar
field in flat spacetime change with inclusion of an overall factor depending
only on the field. The focus of the paper is to obtain analytical results. So,
we show that even though it is possible to perform a field redefinition to get
an equivalent canonical model, it is not always feasible to write the canonical
model in terms of elementary functions. Also, we investigate the behavior of
the energy density and the linear stability of the solutions. Finally, we show
that one can find a class of models that present the same energy density and
the same stability potential.Comment: 6 pages, 4 figure
- …