Cosmologies from higher-order string corrections

Tsujikawa, Shinji

doi:10.1002/andp.200510189

Cited by 16 publications

(9 citation statements)

References 74 publications

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“…This property comes from the fact that the GB term is a Lovelock scalar. Theories with the more general Lagrangian density R /2 + f ( R , P 1 , P 2 ) have been studied by many people in connection to the dark energy problem [142, 110, 521, 420, 585, 64, 166, 543, 180]. These theories are plagued by the appearance of spurious spin-2 ghosts, unless the Gauss-Bonnet (GB) combination is chosen as in the action (12.7) [465, 153, 447] (see also [110, 181, 109]).…”

Section: Gauss-bonnet Gravitymentioning

confidence: 99%

f(R) Theories

Felice

Tsujikawa

2010

Living Rev. Relativ.

3,659

3,400

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Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity — such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.

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Section: Gauss-bonnet Gravitymentioning

confidence: 99%

f(R) Theories

Felice

Tsujikawa

2010

Living Rev. Relativ.

3,659

3,400

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“…This study also shows the instability of the exact solution found in [311], as the initial singularity is approached. The asymptotic behaviour of theories with quadratic corrections to the Einstein-Hilbert were studied, in the context of string cosmology, in [1090,236,1218]. Exponential and power-law FLRW solutions in higher-dimensional string inspired models are found in [855,856,17].…”

Section: Cosmological Solutionsmentioning

confidence: 99%

Modified Gravity and Cosmology

Clifton,

Ferreira,

Padilla

et al. 2011

Preprint

501

847

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In this review we present a thoroughly comprehensive survey of recent work on modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, Scalar-Tensor, Einstein-Aether, and Bimetric theories, as well as TeVeS, f (R), general higher-order theories, Hořava-Lifschitz gravity, Galileons, Ghost Condensates, and models of extra dimensions including Kaluza-Klein, Randall-Sundrum, DGP, and higher co-dimension braneworlds. We also review attempts to construct a Parameterised Post-Friedmannian formalism, that can be used to constrain deviations from General Relativity in cosmology, and that is suitable for comparison with data on the largest scales. These subjects have been intensively studied over the past decade, largely motivated by rapid progress in the field of observational cosmology that now allows, for the first time, precision tests of fundamental physics on the scale of the observable Universe. The purpose of this review is to provide a reference tool for researchers and students in cosmology and gravitational physics, as well as a self-contained, comprehensive and up-to-date introduction to the subject as a whole.

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“…It is tempting to study the string curvature corrections to Einstein gravity amongst which the Gauss-Bonnet correction enjoys special status. A large number of papers are devoted to the cosmological implications of string curvature corrected gravity [2,3,4,5,6,7,8,9,10,11]. These models suffer from several problems.…”

Section: Introductionmentioning

confidence: 99%

Delicatef(R)gravity models with a disappearing cosmological constant and observational constraints on the model parameters

et al. 2008

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We study the f (R) theory of gravity using metric approach. In particular we investigate the recently proposed model by Hu-Sawicki, Appleby − Battye and Starobinsky. In this model, the cosmological constant is zero in flat space time. The model passes both the Solar system and the laboratory tests. But the model parameters need to be fine tuned to avoid the finite time singularity recently pointed in the literature. We check the concordance of this model with the H(z) and baryon acoustic oscillation data. We find that the model resembles the ΛCDM at high redshift. However, for some parameter values there are variations in the expansion history of the universe at low redshift.

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Cosmologies from higher-order string corrections

Cited by 16 publications

References 74 publications

f(R) Theories

f(R) Theories

Modified Gravity and Cosmology

Delicatef(R)gravity models with a disappearing cosmological constant and observational constraints on the model parameters

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