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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, the authors constructed an open singularity-free cosmological model by reconsidering a model originally constructed for a closed universe, which starts from a nonsingular state called prematter governed by an inflationary equation of state P = (γp - 1)ρ where γp (≃ 10-3) is a small positive parameter representing the initial vacuum dominance of the universe.
Abstract: In the light of recent observations which point to an open universe (Ω0 < 1), we construct an open singularity-free cosmological model by reconsidering a model originally constructed for a closed universe. Our model starts from a nonsingular state called prematter, governed by an inflationary equation of state P = (γp - 1)ρ where γp (≃ 10-3) is a small positive parameter representing the initial vacuum dominance of the universe. Unlike the closed models universe cannot be initially static hence, starts with an initial expansion rate represented by the initial value of the Hubble constant H(0). Therefore, our model is a two-parameter universe model (γp,H(0)). Comparing the predictions of this model for the present properties of the universe with the recent observational results, we argue that the model constructed in this work could be used as a realistic universe model.
4 citations
Journal Article•
TL;DR: In this article, a cosmological model in creation field cosmology with varying L in the framework of FRW space-time is investigated and it is shown that creation field increases with time and matter density is constant.
Abstract: A cosmological model in creation field cosmology with varying L in the framework of FRW space-time is investigated. Following Hoyle and Narlikar (1964), we have assumed that universe is filled with dust distribution. To get the deterministic model, we have assumed that Λ=1/R 2 where R is the scale factor. We find that creation field increases with time and matter density is constant which is maintained due to continuous creation of matter. Λ~1/t 2 and particle horizon does not exist. The model represents accelerating universe which matches with the result obtained by Riess et al. (1998) and Perlmutter et al. (1999).
4 citations
01 Jan 2012
TL;DR: In this article, it is observed that for n 1, the models are not physically feasible whereas for n 2, we can generate a class of physically viable models. But, the model of the universe has a transition from early decelerated phase to the recent accelerating phase at present epoch which is consistent with recent astrophysical observations.
Abstract: 1n which yields a time-dependent deceleration parameter. It is observed that for n 1, the models are not physically feasible whereas for n 1, we can generate a class of physically viable models. It is also detected that the models of the universe have a transition from early decelerated phase to the recent accelerating phase at present epoch which is consistent with recent astrophysical observations. The study reveals that massive strings dominate in the early universe. The strings eventually disappear from the universe for sufficiently large times, which is in agreement with current astronomical observations. Some physical and geometric aspects of the models are also discussed. Index Terms—String, Bianchi type I universe, Variable deceleration parameter, Accelerating universe
4 citations
Posted Content•
TL;DR: In this article, the authors considered the hypothesis of antigravitational interaction of elementary particles and antiparticles on the basis of the simple two-component hydrodynamic model with gravitational repulsion and attraction.
Abstract: The hypothesis of antigravitational interaction of elementary particles and antiparticles is considered on the basis of the simple two-component hydrodynamic model with gravitational repulsion and attraction. It is shown increasing of the Jeans instability rate, the presence of antiscreening and the dominative role of the gravitational repulsion as a possible mechanism for spatial separation of matter and antimatter in Universe, as well as the observable acceleration of the far galaxies. The sound wave is found for the two-component gravitational-antigravitational system, which starts for k = 0 in the case of annihilation neglecting. The suggested approach permits to reestablish the idea about baryon symmetry of Universe, causing its steady flatness of the large scale and accelerated Universe expansion.
4 citations
TL;DR: In this paper, a model describing the physical character of the cosmological expansion of the Friedmann-Robertson-Walker closed universe is developed, and the conclusion is drawn that a hidden expansion is superposed on the generally known expansion.
Abstract: In some few steps a model describing the physical character of the cosmological expansion of the Friedmann-Robertson-Walker closed universe is developed. Due to the fact that the rate of the cosmic time is changing, the conclusion is drawn that a hidden expansion is superposed on the generally known expansion of the Universe. The resulting picture-the bi-expansive model-is brought into connection with the voids in the Universe.
4 citations