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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 article, the observational properties of the asymptotic model of the first kind (the so-called Al model) corresponding to the maximum of this dependence are analyzed, for the matter-dominated models, the maximum is achieved at the pointλ = 1.
Abstract: For the case of closed Friedmann models with the cosmological constant, an ‘N - λ’ dependence is plotted, whereN is the conformal time of existence of the Universe, andλ is the ratio of the cosmological constant to its Einstein's value. The observational properties of the asymptotic model of the first kind (the so-called Al model) corresponding to the maximum of this dependence are analyzed. For the matter-dominated models, the maximum is achieved at the pointλ = 1. Formulae for the calculation of the age of the Universe and for that of the photometric distance in the Al model are deduced. The observational properties of the A1 model are compared to the corresponding properties of the standard cosmological model (λ = 0) which does not occupy any special distinguished position on the ‘N - λ’ diagram. It is shown that from the standpoint of the modern observational cosmology these two models cannot be told one from another. However, the A1 model has better standing from the viewpoint of the ‘strong’ wordings of the anthropic cosmological principle.
2 citations
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TL;DR: In this article, a model of the homogenous and isotropic universe is considered in which the coordinate system of reference is not defined by the matter but is a priori specified.
Abstract: The model of the homogenous and isotropic universe is considered in which the coordinate system of reference is not defined by the matter but is a priori specified. The scale factor of the universe changes following the linear law. The scale of mass changes proportional to the scale factor. The temperature of the relativistic matter changes inversly proportional to the root of the scale factor. The model under consideration avoids the flatness and horizon problems. The predictions of the model are fitted to the observational constraints: Hubble parameter, age of the universe, magnitude-redshift relation of the high-redshift supernovae, and primordial nucleosynthesis.
2 citations
TL;DR: In this article, the evolution of the cosmological horizons (particle and event horizons) is studied in an accelerated universe with countably infinitely many constant state equations, and simple expressions in terms of their respective recession velocities are obtained.
Abstract: This paper is the second of two papers devoted to the study of the evolution of the cosmological horizons (particle and event horizons). Specifically, in this paper we consider the extremely general case of an accelerated universe with countably infinitely many constant state equations, and we obtain simple expressions in terms of their respective recession velocities that generalize the previous results for one and two state equations. We also provide a qualitative study of the values of the horizons and their velocities at the origin of the universe and at the far future, and we prove that these values only depend on one dominant state equation. Finally, we compare both horizons and determine when one is larger that the other.
2 citations
31 Mar 2013
TL;DR: In this article, the flat Friedmann universes with stiff fluid and a non-minimally coupled material scalar field with polynomial potentials of the fourth degree were considered in the framework of the Weinberg-Cartan theory.
Abstract: The flat Friedmann universes filled by stiff fluid and a nonminimally
coupled material scalar field with polynomial potentials of the
fourth degree are considered in the framework of the
Einstein-Cartan theory. Exact general solution is obtained for arbitrary positive values of the coupling constant . A comparative analysis of the cosmological models with and without stiff fluid is carried out. Some effects of stiff fluid are
elucidated. It is shown that singular models with a de Sitter asymptotic and with the power-law asymptotic at late times are possible. It is found that is a specific value of the coupling constant. It is demonstrated that the bouncing models without the particle horizon and with an accelerated expansion by a de Sitter law of an evolution at late times are admissible.
2 citations
TL;DR: In this paper, it was shown that the first order thermodynamical particle creation model gives an emergent universe solution even when the chemical potential is non-zero, and that there exists no emergent world scenario in the second order non-equilibrium theory for the particle creation.
Abstract: We show that in the isentropic scenario the first order thermodynamical particle creation model gives an emergent universe solution even when the chemical potential is non-zero. However there exists no emergent universe scenario in the second order non-equilibrium theory for the particle creation model. We then point out a correspondence between the particle creation model with barotropic equation of state and the equation of state giving rise to an emergent universe without particle creation in spatially flat FRW cosmology.
2 citations