Deceleration versus acceleration universe in different frames of F ( R ) gravity
نویسندگان
چکیده
منابع مشابه
Friedmann Equations of FRW Universe in Scalar - tensor Gravity , f ( R ) Gravity and First Law of
In the paper, hep-th/0501055 (R. it is shown that by applying the first law of thermodynamics to the apparent horizon of an FRW universe and assuming the geometric entropy given by a quarter of the apparent horizon area, one can derive the Friedmann equations describing the dynamics of the universe with any spatial curvature; using the entropy formula for the static spherically symmetric black ...
متن کاملf(R) theories of gravity
Modified gravity theories have received increased attention lately due to combined motivation coming from high-energy physics, cosmology and astrophysics. Among numerous alternatives to Einstein’s theory of gravity, theories which include higher order curvature invariants, and specifically the particular class of f(R) theories, have a long history. In the last five years there has been a new st...
متن کاملFriedmann Equations of FRW Universe in Scalar - tensor Gravity , f ( R ) Gravity and First Law of Thermodynamics
In the paper, hep-th/0501055 (R. it is shown that by applying the first law of thermodynamics to the apparent horizon of an FRW universe and assuming the geometric entropy given by a quarter of the apparent horizon area, one can derive the Friedmann equations describing the dynamics of the universe with any spatial curvature; using the entropy formula for the static spherically symmetric black ...
متن کاملStructure formation and generalized second law of thermodynamics in some viable f(R)-gravity models
We investigate the growth of matter density perturbations as well as the generalized second law (GSL) of thermodynamics in the framework of f(R)-gravity. We consider a spatially flat FRW universe filled with the pressureless matter and radiation which is enclosed by the dynamical apparent horizon with the Hawking temperature. For some viable f(R) models containing the Starobinsky, Hu-Sawicki, Exp...
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An instability in the presence of matter in theories of gravity which include a 1/R correction in the gravitational action has been found by Dolgov and Kawasaki. In the present paper this instability is discussed for f(R) gravity in general. We focus on the Palatini formalism of the theory and it is shown that no such instability occurs in this version of f(R) gravity. The reasons for the appea...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 2017
ISSN: 0370-2693
DOI: 10.1016/j.physletb.2017.01.012