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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Efeitos da eletrodin?mica n?o linear na propaga??o de radia??o em torno de objetos compactos carregados

Vasconcelos, Kelder Cavalcanti de 19 December 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-17T23:01:22Z No. of bitstreams: 1 KelderCavalcantiDeVasconcelos_TESE.pdf: 1109145 bytes, checksum: 0466a61f09e9772960e9a9b712348a10 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-20T18:37:43Z (GMT) No. of bitstreams: 1 KelderCavalcantiDeVasconcelos_TESE.pdf: 1109145 bytes, checksum: 0466a61f09e9772960e9a9b712348a10 (MD5) / Made available in DSpace on 2017-04-20T18:37:43Z (GMT). No. of bitstreams: 1 KelderCavalcantiDeVasconcelos_TESE.pdf: 1109145 bytes, checksum: 0466a61f09e9772960e9a9b712348a10 (MD5) Previous issue date: 2016-12-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Nesta tese, a propaga??o de ondas eletromagn?ticas no contexto de eletrodin?micas n?o lineares, ? cuidadosamente analisada dentro de um espa?o-tempo criado por uma massa esfericamente sim?trica e eletricamente carregada. Dentro de certas aproxima??es, verificamos a exist?ncia da auto intera??o eletromagn?tica entre o campo eletrost?tico de fundo e a radia??o que nele se propaga, e adotamos para esta an?lise uma abordagem conhecida como m?trica efetiva. Observamos que a m?trica efetiva n?o gera horizontes de eventos efetivos, por?m as n?o linearidades alteram as posi??es usuais dos horizontes de eventos de buracos negros tipo Reissner-Nordstr?m. Na aproxima??o linear, calculamos como a auto intera??o afeta o desvio geod?sico e o redshift da propaga??o de f?tons pr?ximo destes objetos massivos carregados. Por fim, utilizando a Lagrangeana efetiva de Euler-Heinsenberg, estimamos a contribui??o da auto intera??o no redshift geom?trico perto de objetos compactos extremais. / In this thesis, the propagation of non-linear electromagnetic waves is careful analyzed on a curved spacetime created by spherically symmetric mass and charge distribution. Using certain approximations we verified the existence of electromagnetic selfinteraction between the background electrostatic field and the radiation that propagates on it, and we adopted for this analysis an approach known as effective metric. We observed that the effective metric does not generate effective events horizons, but the non linearities changes the event horizons usual positions of Reissner-Nordstr?m black holes. In linear approximation, we compute how the self-interaction affects the geodesic deviation and the redshift of photons propagating near this massive charged object. Using the Euler-Heisenberg effective Lagrangian, we estimate the contribution of these self-interactions in the geometrical reshift near extremal compact objects.
2

Desigualdades de Penrose e um teorema da massa positiva para buracos negros carregados / Penrose inequalities and apositive mass theorem for charged black roles

Weslley Marinho LozÃrio 24 February 2014 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Apresentamos desigualdades do tipo Penrose e um teorema de massa positiva para buracos negros carregados, isto Ã, dados iniciais para soluÃÃes tempo-simÃtricas das equaÃÃes de Einstein-Maxwell, que podem ser isometricamente mergulhados no espaÃo euclidiano como grÃficos. As demonstraÃÃes usam uma fÃrmula integral para massa ADM de tais hipersuperfÃcies e o fluxo pela curvatura mÃdia inversa. / We present Penrose-type inequalities and a positive mass theorem to charged black roles, ie, initial data for time-symmetric solutions of the Einstein-Maxwell equations, which can be isometrically immersed in Euclidean space as graphics. The statements use an integral formula for the ADM mass of such hypersurfaces and the inverse mean curvature flow.

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