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Particle horizon
About: Particle horizon is a research topic. Over the lifetime, 2096 publications have been published within this topic receiving 69137 citations.
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TL;DR: In this paper, a possible scheme of inflationary scenario at an early stage of the universe during the radiation dominated era by introducing a local Lorentz symmetry violating term in the space-time torsion of Einstein-Cartan action in E(4,1) space was shown.
Abstract: We have shown here, a possible scheme of inflationary scenario at an early stage of the universe during the radiation dominated era by introducing a local Lorentz symmetry violating term in the space-time torsion of Einstein-Cartan action in E(4,1) space. This 'additional' mechanism for producing inflation may also suggest the answer to the question of the local relative abundance of particles over antiparticles in the observed universe.
10 citations
TL;DR: In this article, a class of nonlocal, action-based, and purely gravitational models were proposed to describe a cosmology in which inflation is driven by a large, bare cosmological constant that is screened by the self-gravitation between the soft gravitons that inflation rips from the vacuum.
Abstract: We study a class of nonlocal, action-based, and purely gravitational models. These models seek to describe a cosmology in which inflation is driven by a large, bare cosmological constant that is screened by the self-gravitation between the soft gravitons that inflation rips from the vacuum. Inflation ends with the Universe poised on the verge of gravitational collapse, in an oscillating phase of expansion and contraction that should lead to rapid reheating when matter is included. After the attainment of a hot, dense Universe the nonlocal screening terms become constant as the Universe evolves through a conventional phase of radiation domination. The onset of matter domination triggers a much smaller antiscreening effect that could explain the current phase of acceleration.
10 citations
TL;DR: In this article, the effects of shear on the occurrence of inflation were studied on the basis of a simple model for a spatially closed universe which enters an inflationary era, assuming that the universe enters a vacuumdominated phase in an abrupt transition that occurs everywhere at the same time, and the space-time geometries, before and after the phase transition, are matched to each other via the Lichnerowicz junction conditions.
Abstract: The effects of shear on the occurrence of inflation are studied on the basis of a simple model for a spatially closed universe which enters an inflationary era. It is assumed that the universe enters a vacuum‐dominated phase in an abrupt transition that occurs everywhere at the same time. The space‐time geometries, before and after the phase transition, are matched to each other via the Lichnerowicz junction conditions. The Einstein field equations are solved exactly for a viscous universe of the Kantowski–Sachs type. It is found that the inclusion of (positive) shear retards the occurrence of the vacuum phase transition. The magnitude of this effect depends on the mass of the universe at the time of the phase transition. For a universe with a mass of about 10 kg (which is a value usually associated with the mass of the region from which our universe originated), it is found that the inclusion of shear does not really have a large effect on the time at which the vacuum phase transition occurs. The generality of the results is also discussed.
10 citations
TL;DR: The scale expanding cosmological theory as discussed by the authors assumes that the relationship between space and time could remain constant during the cosmology expansion and all cosmologically locations in time and space could be equivalent, if the metrics of both space and space expand.
Abstract: The Big Bang model assumes that the Universe expands by continuously changing the relationship between the metrics of space and time. However, the relationship between space and time could remain constant during the cosmological expansion and all cosmological locations in time and space could be equivalent, if the metrics of both space and time expand. The Scale Expanding Cosmos theory accurately models the universe we observe and offers simple and direct explanations for several cosmological enigmas.
10 citations
TL;DR: In this article, the authors show that with an array of detectors that we may envision having in a couple of decades, one can in principle measure the change in the anisotropy with two high precision measurements separated by a century.
Abstract: The expansion of the universe may be observed in ``realtime'' by measuring changes in the patterns of the anisotropy in the CMB. As the universe ages, the surface of decoupling--or the CMB photosphere--moves away from us and samples a different gravitational landscape. The response of the CMB to this new landscape results in a different pattern than we observe today. The largest change occurs at l~900. We show that with an array of detectors that we may envision having in a couple of decades, one can in principle measure the change in the anisotropy with two high precision measurements separated by a century.
10 citations