Spherically symmetric solutions of modified field equations in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>f</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>R</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:math>theories of gravity

Multamäki, Tuomas; Vilja, Iiro

doi:10.1103/physrevd.74.064022

Cited by 324 publications

(195 citation statements)

References 32 publications

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“…As such, there are various constraints on the functional form of f (R), coming from theoretical considerations [307][308][309][310], cosmology [311][312][313] and solar system constraints [314][315][316][317][318][319]. Indeed, many of the earliest studied models were ruled on out some of these grounds, with solar system constraints being the most stringent.…”

Section: Example: F (R) Gravitymentioning

confidence: 99%

Beyond the cosmological standard model

et al. 2015

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After a decade and a half of research motivated by the accelerating universe, theory and experiment have a reached a certain level of maturity. The development of theoretical models beyond Λ or smooth dark energy, often called modified gravity, has led to broader insights into a path forward, and a host of observational and experimental tests have been developed. In this review we present the current state of the field and describe a framework for anticipating developments in the next decade. We identify the guiding principles for rigorous and consistent modifications of the standard model, and discuss the prospects for empirical tests.We begin by reviewing recent attempts to consistently modify Einstein gravity in the infrared, focusing on the notion that additional degrees of freedom introduced by the modification must "screen" themselves from local tests of gravity. We categorize screening mechanisms into three broad classes: mechanisms which become active in regions of high Newtonian potential, those in which first derivatives of the field become important, and those for which second derivatives of the field are important. Examples of the first class, such as f (R) gravity, employ the familiar chameleon or symmetron mechanisms, whereas examples of the last class are galileon and massive gravity theories, employing the Vainshtein mechanism. In each case, we describe the theories as effective theories and discuss prospects for completion in a more fundamental theory. We describe experimental tests of each class of theories, summarizing laboratory and solar system tests and describing in some detail astrophysical and cosmological tests. Finally, we discuss prospects for future tests which will be sensitive to different signatures of new physics in the gravitational sector.The review is structured so that those parts that are more relevant to theorists vs. observers/experimentalists are clearly indicated, in the hope that this will serve as a useful reference for both audiences, as well as helping those interested in bridging the gap between them.

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Section: Example: F (R) Gravitymentioning

confidence: 99%

Beyond the cosmological standard model

et al. 2015

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“…In the second approach the Einstein-Hilbert Lagrangian is usually generalized to a function f of the Ricci scalar R. However, at present there are no fully realized and empirically viable f (R) theories that explain the observed level of cosmic acceleration. Furthermore, the f (R) theories suffer from a long-standing controversy about which frame (Einstein or Jordan) is the physical one [22][23][24][25][26]. It should be noted that although we have strong observational evidence for accelerated cosmic expansion but no compelling evidence that the cause of this…”

Section: Introductionmentioning

confidence: 94%

Cosmology in Poincaré gauge gravity with a pseudoscalar torsion

Chee

2016

J. High Energ. Phys.

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A cosmology of Poincaré gauge theory is developed, where several properties of universe corresponding to the cosmological equations with the pseudoscalar torsion function are investigated. The cosmological constant is found to be the intrinsic torsion and curvature of the vacuum universe and is derived from the theory naturally rather than added artificially, i.e. the dark energy originates from geometry and includes the cosmological constant but differs from it. The cosmological constant puzzle, the coincidence and fine tuning problem are relieved naturally at the same time. By solving the cosmological equations, the analytic cosmological solution is obtained and can be compared with the ΛCDM model. In addition, the expressions of density parameters of the matter and the geometric dark energy are derived, and it is shown that the evolution of state equations for the geometric dark energy agrees with the current observational data. At last, the full equations of linear cosmological perturbations and the solutions are obtained.

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“…Bertolami et al [9] have poposed a generalization of ) (R f modified theory of gravity, by including in the theory an explicit coupling of an arbitrary function of the Ricci scalar R with the matter Lagrangian density Lm. Multamaki and Vilja [10,11] investigated vacuum and perfect fluid solutions of spherically symmetric space time in f(R) gravity. .…”

Section: Introductionmentioning

confidence: 99%

N-Dimensional Bianchi Type-I Cosmological Models in f(R,T) Theory of Gravity

Ladke¹,

Hiwarkar²

2014

IJIRSET

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:In this paper, we have obtained two n-dimensional exact solutions of Bianchi type-I space-time in ) , ( T R f theory of gravity using assumption of constant deceleration parameter and variation law of Hubble's parameter which correspond to two different cosmological models with suitable choice of the function ). , ( The physical behavior for both models have been discussed using some physical quantities..

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Spherically symmetric solutions of modified field equations inf(R)theories of gravity

Cited by 324 publications

References 32 publications

Beyond the cosmological standard model

Beyond the cosmological standard model

Cosmology in Poincaré gauge gravity with a pseudoscalar torsion

N-Dimensional Bianchi Type-I Cosmological Models in f(R,T) Theory of Gravity

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