De Sitter Space
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Alguns resultados tipo-Bernstein em variedades semi-riemannianas / Some Bernstein-type results in semi-riemannian manifolds
Nesta tese, estudamos hipersuperfÃcies de tipo-espaÃo completas imersas em variedades semi-Riemannianas, satisfazendo alguma condiÃÃo sobre suas curvaturas de ordem superior, a fim de obtermos resultados tipo-Bernstein. As ferramentas analÃticas que utilizamos sÃo algumas versÃes do princÃpio do mÃximo. No caso em que o ambiente à um espaÃo-tempo
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 05/05/2011
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2. Sobre a geometria de imersÃes isomÃtricas em variedades de Lorentz conformemente estacionÃrias / On the geometry of varieties of isometric immersions in Lorents stationary conformally
In this thesis we study several aspects of the geometry of conformally stationary Lorentz manifolds and, more particularly, of generalized Robertson-Walker spaces, under the presence of a closed conformal vector field. We initiate by focusing our study on the r-stability and on the strong r-stability of closed spacelike hypersurfaces of conformally stationar
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/12/2010
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3. Um teorema de rigidez para hipersuperfÃcies cmc completas em variedades de Lorentz / A rigidity theorem for complete hypersurfaces in Lorentz manifolds
O objetivo deste trabalho à apresentar um teorema de classificaÃÃo para hipersuperfÃcies completas e de curvatura mÃdia constante em variedades de Lorentz de curvatura seccional constante, sob certas limitaÃÃes da curvatura escalar. Para isto usaremos a fÃrmula de Simons, que nos dà uma relaÃÃo entre as transformaÃÃes de Newton Pr e o laplaciano
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/03/2009
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4. Linear pertubations of black roles: stability, quasi-normal modes and tails / Perturbações lineares de buracos negros: estabilidade, modos quase-normais e caudas
Black holes have their proper oscillations, which are called the quasi-normal modes. The proper oscillations of astrophysical black holes can be observed in the nearest future with the help of gravitational wave detectors. Quasi-normal modes are also very important in the context of testing of the stability of black objects, the anti-de Sitter/ Conformal Fie
Publicado em: 2009
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5. Aspectos do Nascimento de um Universo Assintoticamente DeSitter
In this dissertation we revised the canonical quantization of General Relativity, up to the derivation of the Wheeler-deWitt equation. Using that theory, we studied a cosmological model described by a closed Friedmann- Robertson-Walker space-time with radiation and a positive cosmological constant. That model describes, at the quantum level, the birth of an
Publicado em: 2007
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6. Hipersuperficies tipo-espaço com curvatura de ordem superior constante.
Nesta Tese, nossos objetos de estudo s?o as hipersuperf?cies tipo-espa?o imersas num espa?o-tempo com alguma curvatura de ordem superior constante. Em rela??o a estas hipersuperf?cies, abordamos quest?es como exist?ncia, unicidade e estimativa de quantidades geom?tricas associadas as mesmas. Mais precisamente, desenvolvemos f?rmulas tipo-Minkowski para hiper
Publicado em: 2007
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7. The extended ADS/CFT correspondence
The correspondence between conformal covariant fields in Minkowski's space-time and isometric fields in the five dimensional anti-deSitter space-time is extended to a six-dimensional bulk space and its regular sub-manifolds, so as to include the analysis of evaporating Schwarzschild's black holes without loss of quantum unitarity.
Brazilian Journal of Physics. Publicado em: 2005-12
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8. Quantum fields in anti-de Sitter space and the Maldacena conjecture
We review the relation between the Maldacena conjecture, also known as AdS=CFT correspondence, and the so-called holographic principle that seems to be an essential ingredient for a quantum gravity theory. We also illustrate the idea of holography by showing that the curvature of the anti-de Sitter space reduces the number of degrees of freedom making it pos
Brazilian Journal of Physics. Publicado em: 2002-12
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9. On complete spacelike hypersurfaces with constant scalar curvature in the de Sitter space
Let Mn be a complete spacelike hypersurface with constant normalized scalar curvature R in the de Sitter Space S1n + 1. Let H the mean curvature and suppose that
= (R - 1) > 0 and
Anais da Academia Brasileira de Ciências. Publicado em: 2000-12
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10. Biscalar and Bivector Green's Functions in de Sitter Space Time
Biscalar and bivector Green's functions of wave equations are calculated explicitly in de Sitter space time. The calculation is performed by considering the electromagnetic field generated by the spontaneous creation of an electric charge.
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11. SPIN ½ WAVE EQUATION IN DE-SITTER SPACE*
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12. Thermodynamics of cosmological matter creation
A type of cosmological history that includes large-scale entropy production is proposed. These cosmologies are based on reinterpretation of the matter-energy stress tensor in Einstein's equations. This modifies the usual adiabatic energy conservation laws, thereby including irreversible matter creation. This creation corresponds to an irreversible energy flo