Distinguishing modified gravity from dark energy
نویسندگان
چکیده
منابع مشابه
Distinguishing Dark Matter from Modified Gravity
Dynamical mass discrepancies in galaxies have two possible explanations: the existence of large amounts of dark matter or the breakdown of Newtonian gravity. True dark matter halos of galaxies could differ in several respects from apparent halos inferred from misinterpreted modified gravity, and we discuss two observational tests to probe these differences. Modified gravity gives generic, geome...
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There is now strong observational evidence that the expansion of the Universe is accelerating. The standard explanation invokes an unknown "dark energy" component. But such scenarios are faced with serious theoretical problems, which has led to increased interest in models where instead general relativity is modified in a way that leads to the observed accelerated expansion. The question then a...
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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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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...
متن کاملCuscuton Cosmology: Dark Energy meets Modified Gravity
In a companion paper [1], we have introduced a model of scalar field dark energy, Cuscuton, which can be realized as the incompressible (or infinite speed of sound) limit of a k-essence fluid. In this paper, we study how Cuscuton modifies the constraint sector of Einstein gravity. In particular, we study Cuscuton cosmology and show that even though Cuscuton can have an arbitrary equation of sta...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 2008
ISSN: 1550-7998,1550-2368
DOI: 10.1103/physrevd.78.024015