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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 authors investigated the thermodynamic properties of the universe with dark energy and showed that the apparent horizon is the physical horizon in dealing with thermodynamics problems, based on the well known correspondence between the Friedmann equation and the first law of thermodynamics of the visible horizon.
Abstract: We have investigated the thermodynamical properties of the Universe with dark energy Adopting the usual assumption in deriving the constant co-moving entropy density that the physical volume and the temperature are independent, we observed some strange thermodynamical behaviours However, these strange behaviours disappeared if we considered the realistic situation where the physical volume and the temperature of the Universe are related On the basis of the well known correspondence between the Friedmann equation and the first law of thermodynamics of the apparent horizon, we argued that the apparent horizon is the physical horizon in dealing with thermodynamics problems We have concentrated on the volume of the Universe within the apparent horizon and considered that the Universe is in thermal equilibrium with the Hawking temperature on the apparent horizon For dark energy with w ≥ −1, the holographic principle and the generalized second law are always respected

99 citations

Journal ArticleDOI
TL;DR: The Dirac-Milne universe, a matter-antimatter symmetric cosmology, was studied in this paper, where antimatter is supposed to present a negative active gravitational mass.
Abstract: The ΛCDM standard model, although an excellent parametrization of the present cosmological data, contains two as yet unobserved components, dark matter and dark energy, that constitute more than 95% of the Universe. Faced with this unsatisfactory situation, we study an unconventional cosmology, the Dirac-Milne universe, a matter-antimatter symmetric cosmology, in which antimatter is supposed to present a negative active gravitational mass. The main feature of this cosmology is the linear evolution of the scale factor with time, which directly solves the age and horizon problems of a matter-dominated universe. We study the concordance of this model to the cosmological test of type Ia supernovae distance measurements and calculate the theoretical primordial abundances of light elements for this cosmology. We also show that the acoustic scale of the cosmic microwave background naturally emerges at the degree scale despite an open geometry.

97 citations

Journal ArticleDOI
TL;DR: In this article, the authors used holography to determine the nonequilibrium behavior of a strongly coupled nonconformal liquid driven out of equilibrium by the expansion of the universe and developed an expansion for corresponding entropy production in terms of the derivatives of the cosmological scale factor.
Abstract: Microseconds after the Big Bang quarks and gluons formed a strongly coupled nonconformal liquid driven out of equilibrium by the expansion of the Universe. We use holography to determine the nonequilibrium behavior of this liquid in a Friedmann-Lema\^{\i}tre-Robertson-Walker universe and develop an expansion for the corresponding entropy production in terms of the derivatives of the cosmological scale factor. We show that the resulting series has zero radius of convergence and we discuss its resurgent properties. Finally, we compute the resummed entropy production rate in a de Sitter universe at late times and show that the leading order approximation given by bulk viscosity effects can strongly overestimate/underestimate the rate depending on the microscopic parameters.

96 citations

Journal ArticleDOI
TL;DR: In this paper, the early universe dissipative processes in terms of relativistic imperfect fluid formulation are discussed in the context of early universe and particle production of quantized scalar fields in an isotropically expanding space.

96 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the typical voids in the mass distribution in an Ω = 1 universe have a limiting diameter of D 130 h −1 Mpc.
Abstract: Observational constraints on the isotropy of the microwave background on angular scales greater than 1° seriously limit the possible fluctuations in the gravitational potential in the universe because of the Sachs-Wolfe effect. Consequently, they also provide a limit on the initial density inhomogeneities in the universe. We use these limits to show that the typical voids in the mass distribution in an Ω = 1 universe have limiting diameter D 130 h −1 Mpc

95 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202320
202247
20216
202010
201910
201814