25,099 research outputs found
High Temperature Effects on Compactlike Structures
In this work we investigate the transition from kinks to compactons at high
temperatures. We deal with a family of models, described by a real scalar field
with standard kinematics, controlled by a single parameter, real and positive.
The family of models supports kinklike solutions, and the solutions tend to
become compact when the parameter increases to larger and larger values. We
study the one-loop corrections at finite temperature, to see how the thermal
effects add to the effective potential. The results suggest that the symmetry
is restored at very high temperatures.Comment: 6 pages, 4 figures; version to apppear in EPJ
Non BPS topological defect associated with two coupled real field
We investigate a stability equation involving two-component eigenfunctions
which is associated with a potential model in terms of two coupled real scalar
fields, which presents non BPS topological defect.Comment: Revtex, 6 pages, no figures. This work was presented in the XXII
Brazilian National Meeting on Particles and Fields (October/2001), to appear
at http://www.sbf.if.usp.b
On the equivalence of Lambda(t) and gravitationally induced particle production cosmologies
The correspondence between cosmological models powered by a decaying vacuum
energy density and gravitationally induced particle production is investigated.
Although being physically different in the physics behind them we show that
both classes of cosmologies under certain conditions can exhibit the same
dynamic and thermodynamic behavior. Our method is applied to obtain three
specific models that may be described either as Lambda(t)CDM or gravitationally
induced particle creation cosmologies. In the point of view of particle
production models, the later class of cosmologies can be interpreted as a kind
of one-component unification of the dark sector. By using current type Ia
supernovae data, recent estimates of the cosmic microwave background shift
parameter and baryon acoustic oscillations measurements we also perform a
statistical analysis to test the observational viability within the two
equivalent classes of models and we obtain the best-fit of the free parameters.
By adopting the Akaike information criterion we also determine the rank of the
models considered here. Finally, the particle production cosmologies (and the
associated decaying Lambda(t)-models) are modeled in the framework of field
theory by a phenomenological scalar field model.Comment: 9 pages, 3 figures, new comments and 8 references added. Accepted for
publication in Physics Letters
A Representation of the Virasoro Algebra via Wigner-Heisenberg Algebraic Technique to Bosonic Systems
Using the Wigner-Heisenberg algebra for bosonic systems in connection with
oscillators we find a new representation for the Virasoro algebra.Comment: Revised version. Revtex, 7 pages, no figures. This work was presented
in the XXII Brazilian National Meeting on Particles and Fields
(October/2001), to appear in Braz. J. of Phys., 33, 1 (2003
Mass formula for T=0 and T=1 ground states of N=Z nuclei
An algebraic model is developed to calculate the T=0 and T=1 ground state
binding energies for N=Z nuclei. The method is tested in the sd shell and is
then extended to 28-50 shell which is currently the object of many experimental
studies.Comment: 5 figure
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