Black Hole
Mostrando 1-12 de 46 artigos, teses e dissertações.
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1. Desvendando a radiação Hawking
Resumo Buracos negros clássicos, descritos pela relatividade geral, podem absorver partículas, mas não podem emiti-las. Entretanto efeitos quânticos fazem com que buracos negros passem a emitir partículas e comportem-se como um corpo com temperatura diretamente proporcional a κ, a gravidade superficial do buraco negro em questão. Este artigo tem o ob
Rev. Bras. Ensino Fís.. Publicado em: 11/03/2019
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2. Emissão de ondas gravitacionais por fontes compactas: o regime não-linear / Gravitational wave emission from compact sources: the non-linear regime
A colisão de buracos negros é uma das fontes mais importantes de ondas gravitacionais e, em geral, a emissão anisotrópica da radiação causa um recuo do objeto final. Este cenário já é conhecido há décadas, mas foi somente com o recente avanço na relatividade numérica que as velocidades finais dos objetos radiantes foram computadas com precisão.
Publicado em: 2011
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3. Sobre algumas soluções das equações de Einstein com constante cosmológica
In this work, through appropriate coordinate transformations and using Einsteins equations of the general relativity, we show a method to get, from the Minkowski metric, the metric of Friedmann-Lemaıtre-Robertson-Walker, used in cosmology, with the energy-momentum tensor of a perfect isotropic fluid. We obtain also an apparently new solution to Einstein
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/03/2010
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4. Algumas contribuições ao estudo do comportamento de sistemas quânticos na presença de um buraco negro com rotação
Este trabalho trata sobre a influência do campo gravitacional produzido por um buraco negro com rotação sobre sistemas quânticos. Mais especificamente, são consideradas partículas quânticas escalares, que são descritas através da equação de Klein-Gordon. Inicialmente, é mostrado uma maneira através da qual é possíıvel obter a métrica de
Publicado em: 2010
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5. Aspects of nonrelativistic quantum gravity
A nonrelativistic approach to quantum gravity is studied. At least for weak gravitational fields it should be a valid approximation. Such an approach can be used to point out problems and prospects inherent in a more exact theory of quantum gravity, yet to be discovered. Nonrelativistic quantum gravity, e.g., shows promise for prohibiting black holes altoget
Brazilian Journal of Physics. Publicado em: 2009-12
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6. GUP and higher dimensional Reissner-Nordström black hole radiation
Based on the generalized uncertainty principle (GUP), in which the quantum gravitational effects are taken in to account, the corrected Beckenstein-Hawking entropy of the higher dimensional Reissner-Nordström black hole, up to the square order of Planck length, is calculated. Using the corrected entropy, the black hole radiation probability is calculated in
Brazilian Journal of Physics. Publicado em: 2009-09
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7. 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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8. Sobre alguns efeitos quânticos no espaço-tempo de Schwarzschild-de Sitter
In this dissertation we investigate some aspects related with normal modes for scalar fields perturbations of a Schwarzshild-de Sitter black hole. The role played by the cosmological constant A on the reflection and transmission coefficients is studied and analyzed. We also study the Casimir energy density for a massless scalar field confined between two nea
Publicado em: 2009
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9. Simulação Gráfica de Buracos Negros utilizando Sistemas de Partículas
The application of Computer Graphics tools in the nature phenomena simulation have been presenting a series of proposals since its creation. Over the years this task has gained a characteristic trait that makes it closer to the reality, both visually as by the abstraction strategies used. However, the specific application of this Computer Science area for th
Publicado em: 2009
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10. Middleware seguro para redes de sensores sem fio
There is a variety of application scenarios in wireless sensor networks such as medical monitoring, military, home and office security, agriculture and so on. These applications deal with Wireless Sensor Networks (WSNs) odd particularities such as limited power and computational capacities, hardware heterogeneity, low bandwidth, dynamic topology and scalabil
Publicado em: 2009
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11. Fundo estocástico de ondas gravitacionais gerados por buracos negros pré-galáctiocs / Stochastic Background of Gravitational Waves Generated By pre-galactic Black Hole Formation
Observation of the Cosmic Microwave Background Radiation (CMB) provide us with a clear information about the status of matter and radiation at the decoupling era like a snapshot of the Universe 300.000 years after the Big-Bang. Nowadays, through observations of the cosmic structure, we can build-up the history of the Universe from one billion years after the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/02/2008
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12. Qualitative and quantitative features of orbits of massive particles and photons moving in wyman geometry
The Wyman's solution depends on two parameters, the mass M and the scalar charge σ. If one fixes M to a positive value, say M0, and let σ2 take values along the real line it describes three different types of spacetimes. For σ2 > 0 the spacetimes are naked singularities, for σ2 = 0 one has the Schwarzschild black hole of mass M0 and finally for -M0² < �
Brazilian Journal of Physics. Publicado em: 2008-12