Modified Gravity Models of Dark Energy

Tsujikawa, Shinji

doi:10.1007/978-3-642-10598-2_3

Cited by 319 publications

(205 citation statements)

References 326 publications

(652 reference statements)

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“…There are also many reviews of various aspects of modified gravity approaches to the cosmological constant and new physics in the gravitational sector. General reviews of modified gravity are given in [247][248][249][250][251]. More specialized reviews include reviews of f (R) gravity [252][253][254][255]; Chameleon screening [256,257]; galileons [258][259][260][261] and massive gravity [262,263].…”

Section: Organization Of the Reviewmentioning

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: Organization Of the Reviewmentioning

confidence: 99%

Beyond the cosmological standard model

et al. 2015

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“…which gives the solution (27) Replacing this solution into the equation of motion (25) leads to the following equation for the Hubble parameter…”

Section: The Scalar-tensor Model and Field Equationsmentioning

confidence: 99%

“…These models range from modifications of the source terms that involve scalar fields of different nature like quintessence, phantom, tachyion, dilaton (see [8]- [11] for review), including different couplings of scalar field to curvature (scalar-tensor theories) [12]- [20], to modifications of the geometrical terms involving curvature, known as modified gravity theories [21]- [27]. Among all possible explanations for the observed cosmic acceleration the scalar-tensor theories are widely considered since the couplings of scalar fields to curvature naturally appear in the process of quantization on curved space time [28,29], from compactifications of higher dimensional gravity theories [30], in the next to leading order corrections in the α expansion of the string theory [31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Dark energy from Gauss-Bonnet and nonminimal couplings

Granda

Jimenez

2014

Phys. Rev. D

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We consider a scalar-tensor model of dark energy with Gauss-Bonnet and non-minimal couplings. Exact cosmological solutions were found in absence of potential, that give equations of state of dark energy consistent with current observational constraints, but with different asymptotic behaviors depending on the couplings of the model. A detailed reconstruction procedure is given for the scalar potential and the Gauss-Bonnet coupling for any given cosmological scenario. Particularly, we consider conditions for the existence of a variety of cosmological solutions with accelerated expansion, including quintessence, phantom, de Sitter, Little Rip. For the case of quintessence and phantom we have found a scalar potential of the Albrecht-Skordis type, where the potential is an exponential with a polynomial factor. PACS numbers: 98.80. 95.36.+x, 04.50.Kd

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“…The source of this DE can be a scalar field as in quintessential models [4]. Another group of alternative models explore a modification of the Einstein -Hilbert action to explain what we observe [5].…”

Section: Introductionmentioning

confidence: 96%

Asymmetry and dark energy evolution

Cárdenas

2018

J. Phys.: Conf. Ser.

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Abstract. The well known asymmetry of type Ia supernova data is used to infer general features of an alternative model for dark energy. Using a model that allows DE to vary with redshift as a probe, the results indicate the low redshift transition of the deceleration parameter q(z) is evident only taken data points from one hemisphere of the sky. A related effect is a reconstructed DE density X(z) that shows evolution (it decreases as redshift increases) only towards the hemisphere where q(z) manifest the transition. We discuss on possible theoretical frameworks where these effects can be explained.

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Modified Gravity Models of Dark Energy

Cited by 319 publications

References 326 publications

Beyond the cosmological standard model

Beyond the cosmological standard model

Dark energy from Gauss-Bonnet and nonminimal couplings

Asymmetry and dark energy evolution

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