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Full-Text Articles in Physical Sciences and Mathematics

On The Electrovacuum Solutions To The Einstein-Maxwell System In General Relativity, Nelson Camilo Posada Aguirre Aug 2014

On The Electrovacuum Solutions To The Einstein-Maxwell System In General Relativity, Nelson Camilo Posada Aguirre

Theses and Dissertations

In this masters thesis, we will present the analysis of the solution to the Einstein field equation, known as electrovac universe. In this model, an electric charge is located somewhere in an empty universe. An important result from this scenario, is that there is a functional relation between the electrostatic potential and the metric components, asumming a comformastat metric. On the other hand, the Einstein’s equations implies that the metric function satisfy the Laplace equation. We extended this model considering the Einstein’s equation with cosmological constant, which increased the complexity of the equations. The metric function satisfies now a nonlinear …


Perihelion Precession In General Relativity, Charles G. Torre Apr 2014

Perihelion Precession In General Relativity, Charles G. Torre

Charles G. Torre

This is a Maple worksheet providing a relatively quick and informal sketch of a demonstration that general relativistic corrections to the bound Kepler orbits introduce a perihelion precession. Any decent textbook will derive this result. My analysis aligns with that found in the old text "Introduction to General Relativity", by Adler, Bazin and Schiffer. The plan of the analysis is as follows. * Model the planetary orbits as geodesics in the (exterior) Schwarzschild spacetime. * Compute the geodesic equations. * Simplify them using symmetries and first integrals. * Isolate the differential equation expressing the radial coordinate as a function of …


The Spacetime Geometry Of A Null Electromagnetic Field, Charles G. Torre Feb 2014

The Spacetime Geometry Of A Null Electromagnetic Field, Charles G. Torre

Charles G. Torre

We give a set of local geometric conditions on a spacetime metric which are necessary and sufficient for it to be a null electrovacuum, that is, the metric is part of a solution to the Einstein-Maxwell equations with a null electromagnetic field. These conditions are restrictions on a null congruence canonically constructed from the spacetime metric, and can involve up to five derivatives of the metric. The null electrovacuum conditions are counterparts of the Rainich conditions, which geometrically characterize non-null electrovacua. Given a spacetime satisfying the conditions for a null electrovacuum, a straightforward procedure builds the null electromagnetic field from …


Cosmological And Astrophysical Tests Of Modified Gravity, Caixia Gao Jan 2014

Cosmological And Astrophysical Tests Of Modified Gravity, Caixia Gao

Electronic Theses and Dissertations

Three alternative theories to general relativity will be studied. The aim is to test these theories by applying them to astronomical objects or the cosmological background. The first one is unimodular relativity. The cosmological perturbation theory of this model is studied and the predictions on temperature fluctuations of the cmb are found. The second one is drgt massive gravity. In this theory a charged black hole solution is found and compared to those in gr, folloby constraints on the parameter space. The third one is a general massive gravity theory which shares the same background equation with the massless case …