MODIFIED GRAVITATIONAL THEORIES AND COSMIC ACCELERATION
نویسندگان
چکیده
منابع مشابه
Cosmic Acceleration and Modified Gravitational Models ∗
There is now overwhelming observational evidence that our Universe is accelerating in its expansion. I discuss how modified gravitational models can provide an explanation for this observed late-time cosmic acceleration. We consider specific lowcurvature corrections to the Einstein-Hilbert action. Many of these models generically contain unstable de Sitter solutions and, depending on the parame...
متن کاملGravitational energy and cosmic acceleration
Cosmic acceleration is explained quantitatively, as an apparent effect due to gravitational energy differences that arise in the decoupling of bound systems from the global expansion of the universe. “Dark energy” is a misidentification of those aspects of gravitational energy which by virtue of the equivalence principle cannot be localised, namely gradients in the energy due to the expansion o...
متن کاملCosmic Acceleration and Modified Gravity
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...
متن کاملConstraining modified gravitational theories by weak lensing with Euclid
Matteo Martinelli, Erminia Calabrese, Francesco De Bernardis, Alessandro Melchiorri, Luca Pagano, and Roberto Scaramella Physics Department and INFN, Universita’ di Roma ‘‘La Sapienza’’, Ple Aldo Moro 2, 00185, Rome, Italy INAF, Osservatorio Astronomico di Roma, via Frascati 33, 0040 Monte Porzio Catone (RM), Italy (Received 26 October 2010; revised manuscript received 21 December 2010; publish...
متن کاملCosmic Acceleration and M-theory
The status of accelerating four-dimensional universes obtained by timedependent compactifications of 10 or 11 dimensional supergravity is reviewed, as is the ‘no-go’ theorem that they evade. All flat cosmologies for a simple exponential potential are found explicitly. It is noted that transient acceleration is generic, and unavoidable for ‘flux’ compactifications. Included is an eternally accel...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: International Journal of Modern Physics A
سال: 2004
ISSN: 0217-751X,1793-656X
DOI: 10.1142/s0217751x04022578