Results 1 to 10 of about 2,199 (208)
Inhomogeneous M-theory cosmologies [PDF]
Journal of Mathematical Physics, 2002 We study a class of inhomogeneous and anisotropic G2 string cosmological models. In the case of separable G2 models we show that the governing equations reduce to a system of ordinary differential equations. We focus on a class of separable G2 M-theory cosmological models, and study their qualitative behavior (a class of models with time-reversed ...
Coley, Alan A., van den Hoogen, R. J.
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Cosmological theory without singularities [PDF]
Physical Review D, 1993 A theory of gravitation is constructed in which all homogeneous and isotropic solutions are nonsingular, and in which all curvature invariants are bounded. All solutions for which curvature invariants approach their limiting values approach de Sitter space. The action for this theory is obtained by a higher derivative modification of Einstein's theory.
Brandenberger, R. +2 more
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Hamiltonian cosmological perturbation theory [PDF]
Physics Letters B, 2006 The Hamiltonian approach to cosmological perturbations in general relativity in finite space-time is developed, where a cosmological scale factor is identified with spatial averaging the metric determinant logarithm. This identification preserves the number of variables and leads to a cosmological perturbation theory with the scalar potential ...
Barbashov, B. M. +3 more
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Cosmological perturbation theory revisited [PDF]
Classical and Quantum Gravity, 2011 29 pages, no figures, minor ...
Uggla, Claes, Wainwright, John
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Cosmology from string theory [PDF]
Physical Review D, 2007 Version to be published in Physical Review ...
Anchordoqui, Luis +3 more
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String theory and cosmology [PDF]
General Relativity and Gravitation, 1996 We discuss the main cosmological implications of considering string-loop effects and a potential for the dilaton in the lowest order string effective action. Our framework is based on the effective model arising from regarding homogeneous and isotropic dilaton, metric and Yang-Mills field configurations.
Bento, M. C., Bertolami, O.
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SSRN Electronic Journal, 2023 In cosmological special relativity theory, we study Maxwell equations, electromagnetic wave equations and functions. In the cosmological special theory of relativity, we study energy?momentum relations, the Klein-Gordon equation and wave functions. If we solve the Klein?Gordon equation, we obtain the Yukawa potential in the cosmological inertial frame.
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Coarse-grained cosmological perturbation theory [PDF]
Journal of Cosmology and Astroparticle Physics, 2012 Semi-analytical methods, based on Eulerian perturbation theory, are a promising tool to follow the time evolution of cosmological perturbations at small redshifts and at mildly nonlinear scales. All these schemes are based on two approximations: the existence of a smoothing scale and the single-stream approximation, where velocity dispersion of the ...
Pietroni, Massimo +3 more
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Proceedings of The European Physical Society Conference on High Energy Physics — PoS(EPS-HEP 2013), 2014 Plenary talk delivered at the European Physical Society Conference on High Energy Physics, 18-24 July, 2013, Stockholm ...
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Cosmological Perturbation Theory [PDF]
Progress of Theoretical Physics Supplement, 1984 The linear perturbation theory of spatially homogeneous and isotropic universes is reviewed and reformulated extensively. In the first half of the article, a gauge-invariant formulation of the theory is carried out with special attention paid to the geometrical meaning of the perturbation.
Hideo Kodama, Misao Sasaki
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