Stability of the self-accelerating universe in massive gravity

Khosravi, Nima; Niz, Gustavo; Koyama, K.; Tasinato, Gianmassimo

doi:10.1088/1475-7516/2013/08/044

Cited by 50 publications

(60 citation statements)

References 68 publications

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“…Nevertheless, there exist other cosmological solutions: open FLRW [640], and cosmologies with anisotropies in the Stückelberg sector [641-643, 645, 646]. However, perturbations about these solutions appear to be badly-behaved, both linearly [684,[707][708][709][710][711][712][713] and nonlinearly [714][715][716].…”

Section: Self-accelerating Solutions In the Decoupling Limitmentioning

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: Self-accelerating Solutions In the Decoupling Limitmentioning

confidence: 99%

Beyond the cosmological standard model

et al. 2015

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“…When we apply dRGT gravity to cosmology, a self-accelerating solution is found for the open FRW universe [27]. However, follow-up cosmological perturbation analysis found a new ghost instability among the 5 gravitational degrees of freedom [28][29][30][31][32], and further dRGT gravity might suffer from acausality problems [33,34]. The dRGT ghost instability can be eliminated at the expense of introducing a new degree of freedom [35,36].…”

Section: Jhep03(2016)128mentioning

confidence: 99%

Effective field theory of broken spatial diffeomorphisms

Lin

Labun

2016

J. High Energ. Phys.

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We study the low energy effective theory describing gravity with broken spatial diffeomorphism invariance. In the unitary gauge, the Goldstone bosons associated with broken diffeomorphisms are eaten and the graviton becomes a massive spin-2 particle with 5 well-behaved degrees of freedom. In this gauge, the most general theory is built with the lowest dimension operators invariant under only temporal diffeomorphisms. Imposing the additional shift and SO(3) internal symmetries, we analyze the perturbations on a FRW background. At linear perturbation level, the observables of this theory are characterized by five parameters, including the usual cosmological parameters and one additional coupling constant for the symmetry-breaking scalars. In the de Sitter and Minkowski limit, the three Goldstone bosons are supermassive and can be integrated out, leaving two massive tensor modes as the only propagating degrees of freedom. We discuss several examples relevant to theories of massive gravity.

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“…Great effort was devoted to extend at the nonlinear level [1,2] the seminal work of Fierz-Pauli [3] and recently a Boulware-Deser (BD) ghost free theory was found [4,5]. Unfortunately, cosmological solutions of the ghost free De Rham-Gabadaze-Tolley theory are rather problematic: spatially flat homogenous FriedmannRobertson-Walker (FRW) solutions simply do not exist [6] and even allowing for open FRW solutions [7], strong coupling [8] and ghostlike instabilities [9,10] develop. In addition, the cutoff of the theory is rather low [11], namely Λ 3 ¼ ðm 2 M Pl Þ 1=3 .…”

Section: Introductionmentioning

confidence: 99%