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Related papers: The phase space analysis of modified gravity (MOG)

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Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study of exponential infrared $f(T)$ teleparallel gravity to…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Mahmoud Hashim , Amr A. El-Zant , Waleed El Hanafy , Alexey Golovnev

The scalar-tensor theory of Damour and Esposito-Far\`ese recently gained some renewed interest because of its ability to suppress modifications to General Relativity in the weak field, while introducing large corrections in the strong field…

General Relativity and Quantum Cosmology · Physics 2017-09-27 Thibaut Arnoulx de Pirey Saint Alby , Nicolas Yunes

A continuous transition from early Friedmann-like radiation era through to late time cosmic acceleration passing through a long Friedmann-like matter dominated era followed by a second phase of radiation era has been realized in modified…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-08 B. Modak , Kaushik Sarkar , Abhik Kumar Sanyal

The impressive success of the standard cosmological model has suggested to many that its ingredients are all one needs to explain galaxies and their systems. I summarize a number of known problems with this program. They might signal the…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-06 Jacob D. Bekenstein

We study the global stability of a self-gravitating disk in the context of Modified Gravity (MOG) using N-body simulations. This theory is a relativistic scalar-tensor-vector theory of gravity and presented to address the dark matter…

Astrophysics of Galaxies · Physics 2017-05-17 Neda Ghafourian , Mahmood Roshan

We review the evidence for recently accelerating cosmological expansion or "dark energy", either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity), without any Dark Energy constituent. If…

Astrophysics · Physics 2007-05-23 Sidney Bludman

A modified gravity (MOG) possesses a light, neutral vector particle called a ``phion'' associated with a vector field $\phi^\mu$, which forms a cold fluid of Bose-Einstein condensates before recombination with zero pressure and zero shear…

Astrophysics · Physics 2007-05-23 J. W. Moffat

A self consistent effective field theory of modified gravity has recently been proposed with spontaneous breaking of local Lorentz invariance. The symmetry is broken by a vector field with the wrong-sign mass term and it has been shown to…

Astrophysics · Physics 2008-11-26 P. G. Ferreira , B. M. Gripaios , R. Saffari , T. G. Zlosnik

We study the consequences of the $f(R/\Box)$ gravity models for the Solar system and the large scale structure of the universe. The spherically symmetric solutions can be used to obtain bounds on the constant and the linear parts of the…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Tomi S. Koivisto

In this paper we propose and extensively study mimetic $f({\cal G})$ modified gravity models, with various scenarios of cosmological evolution, with or without extra matter fluids. The easiest formulation is based on the use of Lagrange…

General Relativity and Quantum Cosmology · Physics 2015-09-23 Artyom V. Astashenok , Sergei D. Odintsov , V. K. Oikonomou

The acceleration of the universe can be explained either through dark energy or through the modification of gravity on large scales. In this paper we investigate modified gravity models and compare their observable predictions with dark…

Astrophysics · Physics 2008-11-26 Edmund Bertschinger , Phillip Zukin

In contrast to scalar and tensor modes, vector modes of linear perturbations around an expanding Friedmann--Robertson--Walker universe decay. This makes them largely irrelevant for late time cosmology, assuming that all modes started out at…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Golam Mortuza Hossain

In this paper, we have investigated one of the alternative theories to dark matter named MOdified Gravity (MOG) by testing its ability to describe the local dynamics of the Milky Way in vertical and transverse directions with the baryonic…

Astrophysics of Galaxies · Physics 2020-06-15 Zahra Davari , Sohrab Rahvar

I examine how two specific examples of modified gravity explanations of cosmic acceleration help us understand some general problems confronting cosmological tests of gravity: how do we distinguish modified gravity from dark energy if they…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-05 Wayne Hu

We consider cosmology in the Einstein-aether theory (the generally covariant theory of gravitation coupled to a dynamical timelike Lorentz-violating vector field) with a linear aether-Lagrangian. The 3+1 spacetime splitting approach is used…

Astrophysics · Physics 2008-11-26 Baojiu Li , David F. Mota , John D. Barrow

Observational manifestations of some models of modified gravity, which have been suggested to explain the accelerated cosmological expansion, are analyzed for gravitating systems with time dependent mass density. It is shown that if the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 E. V. Arbuzova , A. D. Dolgov

The role of an exponential function of the scalar curvature in the modified gravity is analyzed. Two models are proposed. A toy model that complies with local and cosmological constraints and gives appropriate qualitative description of the…

General Relativity and Quantum Cosmology · Physics 2020-07-15 L. N. Granda

We investigate a conformal invariant gravitational model which is taken to hold at pre-inflationary era. The conformal invariance allows to make a dynamical distinction between the two unit systems (or conformal frames) usually used in…

High Energy Physics - Theory · Physics 2009-11-10 Yousef Bisabr

Recent analyses of wide-area radio-galaxy surveys have reported a statistically significant excess in the cosmic number-count dipole, with an amplitude exceeding the purely kinematic expectation of the standard $\Lambda$CDM model by a…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-13 John. W. Moffat

We investigate the cosmological consequences of the modified Friedmann equations when the entropy associated with the apparent horizon, given by Barrow entropy, $S\sim A^{1+\delta/2}$, where $0\leq\delta\leq1$, represents the amount of the…

General Relativity and Quantum Cosmology · Physics 2023-01-18 Ahmad Sheykhi
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