Gravitation Theory
Mostrando 13-24 de 41 artigos, teses e dissertações.
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13. Analogue of the theorem of Birkhoff in a metric nonsymmetric theory of the gravitational-electromagnetic field
We prove that a spherically symmetric exterior solution of the field equations of a metric nonsymmetric theory of gravitation coupled with the electromagnetic field is necessarily static.
Brazilian Journal of Physics. Publicado em: 2007-06
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14. Cosmologia na teoria de Visser / Cosmology from the Visser s theory
The advent of observational cosmology has led us to conclude that only 4% of whole Universe is composed by known matter (baryons). On the other hand 23% comes from a kind of non barionic dark matter. Moreover the cosmic dynamics is almost fully dominated by the so called dark energy (usually considered a kind of fluid), which corresponds to 73% of the energy
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/08/2006
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15. Metric nonsymmetric theory of gravitation: the analogue of the theorem of Birkhoff
We prove that a spherically symmetric solution of the field equations of the metric nonsymmetric theory of gravitation developed previously is necessarily static.This is the analogue of the well known Birkhoff theorem in general relativity.
Brazilian Journal of Physics. Publicado em: 2006-12
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16. Interior problem in a ponsymmetric theory of gravitation
The field equations of a previous metric nonsymmetric theory of gravitation are considered for the interior of a static spherically symmetric perfect fluid with a view to a study of stellar equilibrium. The equations are put into a form of four first-order differential equations which are ready for numerical integration.
Brazilian Journal of Physics. Publicado em: 2006-06
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17. Cosmologia na teoria de Visser / Cosmology from the Visser s theory
The advent of observational cosmology has led us to conclude that only 4% of whole Universe is composed by known matter (baryons). On the other hand 23% comes from a kind of non barionic dark matter. Moreover the cosmic dynamics is almost fully dominated by the so called dark energy (usually considered a kind of fluid), which corresponds to 73% of the energy
Publicado em: 2006
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18. Cosmologia na teoria de Visser / Cosmology from the Visser s theory
O advento da cosmologia observacional tem nos levado à conclusão de que apenas 4% do Universo é constituído pela matéria conhecida (bárions). Por outro lado 23% correspondem à matéria escura não bariônica, enquanto o domínio da dinâmica cósmica foi legado à, assim chamada, energia escura (geralmente considerada um tipo de fluido), correspondend
Publicado em: 2006
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19. Conservation laws in a metric nonsymmetric theory of gravitation
The conservation laws associated with a previously studied metric nonsymmetric theory of gravitation are established and their physical significance is discussed. Conservation laws are obtained for the generalized energy and momentum. Some applications of the results are made for a spherically symmetric fluid with a view to future study of stelar equilibrium
Brazilian Journal of Physics. Publicado em: 2005-12
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20. Reflexões e contribuições para o ensino de gravitação clássica no nível médio
The subject of Classic Gravitation is part of the actual curriculum for High School in Brazil, and it is taught in the first year of that education level. This master thesis presents a research regarding the subject Classic Gravitation in High School. This research was based in two complementary guidelines of research and action. The first guideline was the
Publicado em: 2005
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21. Dark matter halos and scalar fields / Halos de matéria escura e campos escalares
Nearly twenty five percent of the energetic content of the universe appears in a form that is still unknown and is named dark matter. Since the first speculations about its existence (Zwicky ~1933), many models have been proposed trying to justify all the observed data but, until now, none of them has been able to solve this problem. In this monography, we w
Publicado em: 2005
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22. Selected topics in teleparallel gravity
Teleparallel gravity can be seen as a gauge theory for the translation group. As such, its fundamental field is neither the tetrad nor the metric, but a gauge potential assuming values in the Lie algebra of the translation group. This gauge character makes of teleparallel gravity, despite its equivalence to general relativity, a rather peculiar theory. A fir
Brazilian Journal of Physics. Publicado em: 2004-12
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23. Non gravitational black holes
Analogue models of general relativity have recently been considered with great interest by the scientific community. They connect branches of physics as different as gravitation, condensed matter physics, electrodynamics, acoustics, and quantum field theory. One of the main expectations about such models lies on the possibility of testing in laboratory some
Brazilian Journal of Physics. Publicado em: 2004-12
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24. Ghost free analysis of a nonsymmetric theory of gravitation
The absence of ghost-negative energy radiative modes in a proposed generalized theory of gravitation based on a non-symmetric metric is reanalyzed. The missing contribution of the symmetric sector of the Lagrangian is calculated and shown to be null. The ghost free character of the theory is then firmly established.
Brazilian Journal of Physics. Publicado em: 2003-12