Inhomogeneity implies accelerated expansion
نویسندگان
چکیده
منابع مشابه
Accelerated expansion through interaction
Interactions between dark matter and dark energy with a given equation of state are known to modify the cosmic dynamics. On the other hand, the strength of these interactions is subject to strong observational constraints. Here we discuss a model in which the transition from decelerated to accelerated expansion of the Universe arises as a pure interaction phenomenon. Various cosmological scenar...
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The present paradigm in cosmology is the usual Big-Bang Cosmology in which two stages of accelerated expansion are incorporated: the inflationary phase in the very early universe which produces the classical inhomogeneities observed in the universe, and a second stage of acceleration at the present time as the latest Supernovae observations seem to imply. Both stages could be produced by a scal...
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The fact that the ΛCDM model fits the observations does not necessarily imply the physical existence of ‘dark energy’. Dropping the assumption that cold dark matter (CDM) is a perfect fluid opens the possibility to fit the data without dark energy. For imperfect CDM, negative bulk pressure is favoured by thermodynamical arguments and might drive the cosmic acceleration. The coincidence between ...
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The currently available cosmological data yield, as a most striking result, that the expansion rate of the universe seems to be increasing at late times, contrary to the standard (zero cosmological constant) FLRW prediction. The usual explanation for this discrepancy is that a new component of the energy density of the universe, known as dark energy, dominates this recent evolution. Since the e...
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We show that the recently suggested explanations of cosmic acceleration by the modification of gravity at small curvature suffer violent instabilities and strongly disagree with the known properties of gravitational interactions. It seems established that at the present epoch the universe expands with acceleration. It follows directly from the observation of high red-shift supernovae [1] and in...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 2014
ISSN: 1550-7998,1550-2368
DOI: 10.1103/physrevd.89.043506