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The nature of the fuel that drives today's cosmic acceleration is an open and tantalizing mystery. The braneworld theory of Dvali, Gabadadze, and Porrati (DGP) provides a context where late-time acceleration is driven not by some…

Astrophysics · Physics 2009-11-10 Arthur Lue , Roman Scoccimarro , Glenn D. Starkman

We study the growth of large scale structure in two recently proposed non-standard cosmological models: the brane induced gravity model of Dvali, Gabadadze and Porrati (DGP) and the Cardassian models of Freese and Lewis. A general formalism…

Astrophysics · Physics 2009-11-07 T. Multamaki , E. Gaztanaga , M. Manera

We derive the modified Friedmann equations for a generalization of the Dvali-Gabadadze-Porrati (DGP) model in which the brane has one additional compact dimension. The main new feature is the emission of gravitational waves into the bulk.…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Florian Niedermann , Robert Schneider

Modifications of gravity have been considered to model the primordial inflation and the late-time cosmic acceleration. Provided that modified gravity models do not suffer from theoretical instabilities, they must be confronted with…

General Relativity and Quantum Cosmology · Physics 2016-10-13 Sandrine Schlögel

The motive of this work is to study gravitational collapse in Vaidya space-time embedded in Galileon gravity theory. Galileon gravity is in fact an infrared modification of Einstein gravity, which was proposed as a generalization of the 4D…

General Physics · Physics 2015-06-18 Prabir Rudra , Ujjal Debnath

In a recent paper, Alimi & Koskas highlighted in $w$CDM models derived from general relativity (GR) (with Dark Energy Universe numerical simulation data), a cosmological invariance of the distribution of dark-matter (DM) halo shapes when…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-08 Remy Koskas , Jean-Michel Alimi

Braneworld models with induced gravity have the potential to replace dark energy as the explanation for the current accelerating expansion of the Universe. The original model of Dvali, Gabadadze and Porrati (DGP) demonstrated the existence…

High Energy Physics - Theory · Physics 2008-11-26 Marcela Carena , Joseph Lykken , Minjoon Park , Jose Santiago

It is a well-known fact that the gravitational effect of dark matter in galaxies is only noticeable when the orbital accelerations drop below $a_0 \simeq 2\times 10^{-8}$ cm s$^{-1}$ (Milgrom's Law). This peculiarity of the dynamic…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-08 L. Acedo

It is shown that a disformally coupled theory in which the gravitational sector has the Einstein-Hilbert form is equivalent to a quartic DBI Galileon Lagrangian, possessing non-linear higher derivative interactions, and hence allowing for…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-02 Miguel Zumalacarregui , Tomi S. Koivisto , David F. Mota

We study the growth of subhorizon perturbations in brane-induced gravity using perturbation theory. We solve for the linear evolution of perturbations taking advantage of the symmetry under gauge transformations along the extra-dimension to…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-10 Roman Scoccimarro

There has been a lot of research interest in modified gravity theories which utilise the Vainshtein mechanism to recover standard general relativity in regions with high matter density, such as the Dvali-Gabadadze-Porrati and Galileon…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-24 Baojiu Li , Gong-Bo Zhao , Kazuya Koyama

By considering the nonrelativistic limit of de-Sitter geometry one obtains the nonrelativistic space-time with a cosmological constant and Newton-Hooke (NH) symmetries. We show that the NH symmetry algebra can be enlarged by the addition of…

High Energy Physics - Theory · Physics 2014-11-18 J. Lukierski , P. C. Stichel , W. J. Zakrzewski

We study the gravitational collapse of an overdensity of nonrelativistic matter under the action of gravity and a chameleon scalar field. We show that the spherical collapse model is modified by the presence of a chameleon field. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Ph. Brax , R. Rosenfeld , D. A. Steer

Chameleon, environmentally dependent dilaton, and symmetron gravity are three models of modified gravity in which the effects of the additional scalar degree of freedom are screened in dense environments. They have been extensively studied…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Anne-Christine Davis , Ruth Gregory , Rahul Jha , Jessica Muir

The accelerating expansion of our universe at present could be driven by an unknown energy component (Dark Energy) or a modification of general relativity (Modified Gravity). In this note we revisit the constraints on a phenomenological…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-03 Jun-Qing Xia

We revisit the construction of models of quantum gravity in d dimensional Minkowski space in terms of random tensor models, and correct some mistakes in our previous treatment of the subject. We find a large class of models in which the…

High Energy Physics - Theory · Physics 2024-08-26 Tom Banks , Willy Fischler

We review the different frameworks in which Galileon scalar fields have been seen to emerge such an in DGP, New Massive Gravity and Ghost-free massive Gravity and emphasize their relation with the Lovelock invariant in braneworld models.…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-20 Claudia de Rham

We present a halo mass function accurate over the full relevant Hu-Sawicki $f(R)$ parameter space based on spherical collapse calculations and calibrated to a suite of modified gravity $N$-body simulations that include massive neutrinos. We…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Steffen Hagstotz , Matteo Costanzi , Marco Baldi , Jochen Weller

Galaxies residing in dark matter halos exert significant gravitational effects that alter halo structure and dynamics. The complexity of these interactions escalates with the diversity of galactic structures and the variability in dark…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-28 Daneng Yang

We covariantize the decoupling limit of massive gravity proposed in arXiv:1011.1232 and study the cosmology of this theory as a proxy, which embodies key features of the fully non-linear covariant theory. We first confirm that it exhibits a…

High Energy Physics - Theory · Physics 2012-03-02 Claudia de Rham , Lavinia Heisenberg
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