Late-time cosmic acceleration: ABCD of dark energy and modified theories of gravity
نویسندگان
چکیده
منابع مشابه
Holographic dark energy and late cosmic acceleration
It has been persuasively argued that the number of the effective degrees of freedom of a macroscopic system is proportional to its area rather than to its volume. This entails interesting consequences for cosmology. Here we present a model based on this “holographic principle” that accounts for the present stage of accelerated expansion of the Universe and significantly alleviates the coinciden...
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The recently observed accelerating cosmological expansion or ”dark energy” may be either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity) without any constituent Dark Energy. Lowor high-curvature modifications of Einstein gravity are distinguished by the spacetime (Ricci) curvature of their vacua. If constituent Dark Energy does not exist, s...
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Abstract I briefly discuss some attempts to construct a consistent modification to General Relativity (GR) that might explain the observed late-time acceleration of the universe and provide an alternative to dark energy. I mention the issues facing extensions to GR, illustrate these with two specific examples, and discuss the resulting observational and theoretical obstacles. This article compr...
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This phenomenological review stresses the distinction between kinematics), the description of the recently inflationary universe (cosmography), and dynamics, the mechanism driving this accelerating expansion. Because the homogeneous expansion history H(z) of the universe measures only kinematic variables, it cannot fix the underlying dynamics: cosmographic measurements of the homogeneous univer...
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Explanations of the late-time cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are mostly based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common – an inability to account for the gravitational properties of the vacuum energy, and a failure t...
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ژورنال
عنوان ژورنال: International Journal of Modern Physics D
سال: 2016
ISSN: 0218-2718,1793-6594
DOI: 10.1142/s0218271816300317