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We systematically review some standard issues and also the latest developments of modified gravity in cosmology, emphasizing on inflation, bouncing cosmology and late-time acceleration era. Particularly, we present the formalism of standard…

General Relativity and Quantum Cosmology · Physics 2021-05-25 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

We develop the general scheme for modified $f(R)$ gravity reconstruction from any realistic FRW cosmology. We formulate several versions of modified gravity compatible with Solar System tests where the following sequence of cosmological…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

The solution of dark energy problem in the models without scalars is presented. It is shown that late-time accelerating cosmology may be generated by the ideal fluid with some implicit equation of state. The universe evolution within…

High Energy Physics - Theory · Physics 2009-09-17 Shin'ichi Nojiri , Sergei D. Odintsov , O. G. Gorbunova

In this letter, we consider the possibility of reconciling metric theories of gravitation with violation of the conservation of energy-momentum. Under some circumstances, this can be achieved in the context of unimodular gravity, and it…

General Relativity and Quantum Cosmology · Physics 2017-01-18 Thibaut Josset , Alejandro Perez , Daniel Sudarsky

In recent times, Discrete Space Time Architectures are being considered, in the context of Quantum Gravity, Quantum Super Strings, Dark Energy and so on. We show that such a scheme is intimately tied up with a varying $G$ cosmology, which…

General Physics · Physics 2009-11-10 B. G. Sidharth

A web of interlocking observations has established that the expansion of the Universe is speeding up and not slowing, revealing the presence of some form of repulsive gravity. Within the context of general relativity the cause of cosmic…

Astrophysics · Physics 2008-11-26 Michael S. Turner , Dragan Huterer

We investigate the cosmological implications of a new class of modified gravity, where the field equations generically include higher-order derivatives of the matter fields, arising from the introduction of non-dynamical auxiliary fields in…

General Relativity and Quantum Cosmology · Physics 2016-07-01 Tiberiu Harko , Francisco S. N. Lobo , Emmanuel N. Saridakis

We study the cosmological evolution of an induced gravity model with a scale symmetry breaking potential for the scalar field. The radiation to matter transition, following inflation and reheating, influences the dynamics of such a field…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Alexander Y. Kamenshchik , Alessandro Tronconi , Giovanni Venturi

By relaxing the conventional assumption of a purely gravitational interaction between dark energy and dark matter, substantial alterations to the growth of cosmological structure can occur. In this work we focus on the homogeneous transfer…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-08 Fergus Simpson , Brendan M. Jackson , John A. Peacock

There is now strong evidence that the current energy density of the Universe is dominated by dark energy with an equation of state w<-1/3, which is causing accelerated expansion. The build-up of structure within such Universes is subject to…

Astrophysics · Physics 2008-11-26 Will J. Percival

The cosmographic technique is a powerful model-independent tool for distinguishing between competing cosmological scenarios. The key strengths and weaknesses of standard cosmography are discussed in view of healing the convergence problem…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-01 Salvatore Capozziello , Rocco D'Agostino

The expansion of the Universe is accelerating, as testified by observations of supernovae of type Ia as a function of redshift. Explanations are of two types: modifications of Einstein gravity or new forms of energy, coined dark energy.The…

Astrophysics · Physics 2007-05-23 Matts Roos

Despite two decades of tremendous experimental and theoretical progress, the riddle of the accelerated expansion of the Universe remains to be solved. On the experimental side, our understanding of the possibilities and limitations of the…

The discovery ten years ago that the expansion of the Universe is accelerating put in place the present cosmological model, in which the Universe is composed of 4% baryons, 20% dark matter, and 76% dark energy. Yet the underlying cause of…

Cosmology and Nongalactic Astrophysics · Physics 2009-04-17 Joshua A. Frieman

In the present work, we review some general aspects of modified gravity theories, investigating mathematical and physical properties and, more specifically, the feature of viable and realistic models able to reproduce the dark energy epoch…

General Relativity and Quantum Cosmology · Physics 2013-10-16 Ratbay Myrzakulov , Lorenzo Sebastiani , Sergio Zerbini

The exact solution for dynamic of conform-flat space homogeneous since dynamic equation is given. Conform mode of space metric changing in Global time theory has negative energy density. Swap of energy to this mode from another ones lead to…

General Relativity and Quantum Cosmology · Physics 2007-05-23 D. Burlankov

We discuss the evolution of density perturbations of dark matter and dark energy in cosmological models which admit future singularities in a finite time. Up to now geometrical tests of the evolution of the universe do not differentiate…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-10 Tomasz Denkiewicz

The discovery ten years ago that the expansion of the Universe is accelerating put in place the last major building block of the present cosmological model, in which the Universe is composed of 4% baryons, 20% dark matter, and 76% dark…

Astrophysics · Physics 2009-02-27 Joshua Frieman , Michael Turner , Dragan Huterer

In this work, we review a plethora of modified theories of gravity with generalized curvature-matter couplings. The explicit nonminimal couplings, for instance, between an arbitrary function of the scalar curvature $R$ and the Lagrangian…

General Relativity and Quantum Cosmology · Physics 2014-07-29 Tiberiu Harko , Francisco S. N. Lobo

Towards the goal to quantize gravity, in this short review we discuss an intermediate step which consists in extending the picture of standard General Relativity by considering Extended Theories of Gravity. In this tapestry, the equations…

General Relativity and Quantum Cosmology · Physics 2014-03-03 Christian Corda
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