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Showing 1 to 20 of 76 for “"spherically symmetric"”.
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Near-critical spherically symmetric accretion by neutron stars
Submitted by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-24T20:23:01Z No. of bitstreams: 1 1993_fortner.pdf: 5017205 bytes, checksum: 1bb2f5533aab19fc255c0d3894022c3a (MD5)
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The effects of light propagation in spherically symmetric metrics.
Massachusetts Institute of Technology. Dept. of Physics. Thesis. 1969. Ph.D.
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Spherically-symmetric inhomogeneities in general relativity and their effects in cosmology
Spherically-symmetric solutions are relevant in many areas of cosmology, from perturbations in the early Universe to growth of large scale structures in the later eras. In this thesis, we first focus on a comparison between the tetrad-based method and the widely used Lemaitre-Tolman-Bondi (LTB) …
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A Mathematical Study of Hawking Radiation on Collapsing, Spherically Symmetric Spacetimes
… bosons emitted by a family of collapsing, spherically symmetric, charged models of black hole formation, including both extremal and sub-extremal black holes. We further bound the rate at which the late time behaviour is approached. This treatment relies heavily on analysing the behaviour …
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Aspects of a spherically symmetric model of the post-decoupling universe
… aim of this thesis is to consider aspects of the spherically symmetric Lemaitre-Tolman-Bondi (LTB) solution as a model of the post-decoupling universe. To do this comprehensively is a massive task and is not our aim here. Indeed, far from it, we will concentrate on select instances of this …
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Spherically symmetric dark energy structures in the context of Chaplygin gas model
This paper investigates the existence of spherically symmetrical dark energy structures under the context of Chaplygin gas. A scaling solution of the form r -2/3 is found for the density and then we calculated the corresponding rotational curve and it turns out to be unrealistic implying that such …
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A study of solutions and perturbations of spherically symmetric spacetimes in fourth order gravity.
… solutions and perturbations of rotationally symmetric spacetimes in f(R) gravity, one of the most widely studied classes of fourth order gravity. We begin by introducing f(R) theories of gravity and present the general equations for these theories. We investigate the problem of matching …
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Quantum Effects of the Massless Spin One-Half Field in Static Spherically Symmetric Black Hole and Wormhole Spacetimes
… and on and outside the throat of three static spherically symmetric Lorentzian wormhole spacetimes. The field and all spacetimes studied are in a zero temperature vacuum state. We treat the field quantum mechanically on a classical background spacetime governed by general relativity. The full …
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1+1+2 covariant approach to gravitational lensing in f(R) gravity
… devised for General Relativity, to treat spherically symmetric spacetimes in for fourth order theories of gravity. Using this formalism, we derive equations for a static and spherically symmetric spacetime for general f(R) gravity. We apply these master eqautions to derive some exact …
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SOLAR MODULATION OF GALACTIC COSMIC RAYS: TECHNIQUES & APPLICATIONS (SHOCK ACCELERATION, ANTIPROTONS)
… first part involves the time-dependent, spherically-symmetric, solar modulation of galactic cosmic rays. A numerical technique was introduced for the solution of this problem. A model for the solar-cycle variation in cosmic-ray intensity illustrated this method, using enhanced particle …
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Total mass of a patch of a matter-dominated Friedmann-Robertson-Walker universe
… the total relativistic mass for a patch of a spherically-symmetric matter-dominated spacetime of negative curvature. This calculation provides the open-universe analogue to a similar calculation first proposed by Zel'dovich in 1962. I consider a finite, spherically-symmetric (SO(3)) spatial …
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Constrained dynamics and higher derivative systems in modified gravity
… In the second part of the thesis, we study the spherically symmetric static solution of a class of two scalar-field theory, where one of them is a Lagrange multiplier enforcing a constraint relating the value of the other scalar field to the norm of its derivative. We find the spherically …
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Approaches to ensembles of universes
… the behaviour of such transition regions for spherically symmetric space-times. In the last part of this thesis I discuss philosophical, physical, and probabilistic issues related to the concept of a multiverse - an ensemble of universes. The difference between ensembles of really existing …
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Continuum structure in strong electromagnetic fields
… ] In this chapter, the Dirac equation for spherically symmetric potentials is closely examined. Analytical solutions are found for a square well potential, the properties of which will be used later when the equation is solved for arbitrary potentials using numerical methods. The starting …
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Mathematical Models of Prevascular Tumor Growth by Diffusion
… and thus the equations are of diffusion type in spherically symmetric geometries. Since a key characteristic of cancerous diseases is uncontrolled growth, the sensitivity of a model to the nature of different mitotic control functions is examined and the stability of subsequent tissue growth is …
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Finite-strength shock propagation for alternative equations of state
… of Lie groups, the invariance properties of the spherically symmetric equations of gasdynamics are determined and used to construct invariant equations of state. The invariant functions of this group are next introduced as the new dependent and independent variables along with an additional …
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Aspects of holography in Lorentz-violating gravity
… in the low energy limit, it possesses static and spherically symmetric solutions with 'universal horizons'---spacelike hypersurfaces that are causal boundaries between an interior region and asymptotic spatial infinity. In other words, this theory admits black hole solutions but with very …
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