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Here we propose the extended modified gravity theory named as $f(R,G,\mathcal{T})$ gravity where $R$ is the Ricci scalar, $G$ is the Gauss-Bonnet invariant and $\mathcal{T}$ is the trace of the stress-energy tensor. We derive the…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Ujjal Debnath

In recent years, modifications to General Relativity (GR) have been explored to address cosmological observations, particularly in the context of late-time cosmic acceleration. Among these, modifications based on the Teleparallel Equivalent…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Saurabh Verma , Archana Dixit , Anirudh Pradhan , M. S. Barak

From a previous paper where we proposed a description of general relativity within the gravito-electromagnetic limit, we propose an alternative modified gravitational theory. As in the former version, we analyze the vector and tensor…

General Relativity and Quantum Cosmology · Physics 2022-05-03 Sergio Giardino

We provide a cosmological test of modified gravity with two tensorial degrees of freedom and no extra propagating scalar mode. The theory of gravity we consider admits a cosmological model that is indistinguishable from the $\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-01 Takashi Hiramatsu , Tsutomu Kobayashi

We comment on arXiv:1112.1320 and point out that baryonic oscillations of the matter power spectrum, while predicted by theories that do not incorporate collisionless cold dark matter, are strongly suppressed by the statistical window…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-20 J. W. Moffat , V. T. Toth

A recent paper studies a modification of Einstein-aether theory in which the aether vector is restricted, at the level of the action, to be the gradient of a scalar. In this comment we note that this scalar version of Einstein-aether theory…

General Relativity and Quantum Cosmology · Physics 2014-06-13 Ted Jacobson , Antony J. Speranza

In a recent paper, "Reexamining $f\left(R,T\right)$ gravity", by S. B. Fisher and E. D. Carlson, Phys. Rev. D 100, 064059 (2019), the authors claim that for the particular $f(R,T)$ modified gravity model, with $f(R,T)=f_1(R)+f_2(T)$, the…

General Relativity and Quantum Cosmology · Physics 2020-03-19 Tiberiu Harko , Pedro H. R. S. Moraes

The construction of conformally invariant gauge conditions for Maxwell and Einstein theories on a manifold M is found to involve two basic ingredients. First, covariant derivatives of a linear gauge (e.g. Lorenz or de Donder), completely…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Giampiero Esposito , Cosimo Stornaiolo

We explore the recently introduced modified Gauss-Bonnet gravity [1], $f(\mathcal{G},T)$ pragmatic with $\mathcal{G}$, the Gauss-Bonnet term, and ${T}$, the trace of the energy-momentum tensor. Noether symmetry approach has been used to…

General Physics · Physics 2017-01-31 M. Farasat Shamir , Mushtaq Ahmad

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 study the motion of particles in the background of a scalar-tensor theory of gravity in which the scalar field is kinetically coupled to Einstein tensor. We constrain the value of the derivative parameter $z$ through solar system tests.…

General Relativity and Quantum Cosmology · Physics 2020-12-02 P. A. González , Marco Olivares , Eleftherios Papantonopoulos , Yerko Vásquez

In this article we construct a massive theory of gravity that is invariant under conformal transformations. The massive action of the theory depend on the metric tensor and a scalar field, which are considered as the only field variables.…

General Relativity and Quantum Cosmology · Physics 2014-12-16 F. F. Faria

We perform detailed investigation of cosmological perturbations in f(T) theory of gravity coupled with scalar field. Our work emphasizes on the way to gauge fix the theory and we examine all possible modes of perturbations up to second…

General Relativity and Quantum Cosmology · Physics 2013-06-24 Keisuke Izumi , Yen Chin Ong

We conjecture that any modification of general relativity can be studied by the minimal geometric deformation approach provided that such modification can be represented by a traceless energy-momentum tensor.

General Relativity and Quantum Cosmology · Physics 2017-08-30 J Ovalle , R Casadio , A Sotomayor

Modified gravity provides a possible explanation for the currently observed cosmic accelaration. In this paper, we study general classes of modified gravity models. The Einstein-Hilbert action is modified by using general functions of the…

Astrophysics · Physics 2008-11-26 Antonio De Felice , Pia Mukherjee , Yun Wang

We consider a general scalar-tensor theory of gravity and review briefly different forms it can be presented (different conformal frames and scalar field parametrizations). We investigate the conditions under which its field equations and…

General Relativity and Quantum Cosmology · Physics 2015-02-02 Laur Jarv , Piret Kuusk , Margus Saal , Ott Vilson

We investigate sufficient conditions under which cubic gravity is healthy and viable at the perturbation level. We perform a detailed analysis of the scalar and tensor perturbations. We impose the requirement that the two scalar potentials,…

General Relativity and Quantum Cosmology · Physics 2024-02-19 Petros Asimakis , Spyros Basilakos , Emmanuel N. Saridakis

In this work we present a brief discussion about modified and extended cosmological models using current observational tests. We show that according to these astrophysical samples based in late universe measurements, theories like $f(R)$…

General Relativity and Quantum Cosmology · Physics 2021-01-25 Celia Escamilla-Rivera

In this short note we find covariant canonical formulation of modified Eddington gravity action coupled to scalar field. We also discuss limitation of this formulation and suggest its possible generalization.

High Energy Physics - Theory · Physics 2025-03-03 J. Kluson

Possible models of modified gravity are being extensively studied now, with most phenomenological motivations coming from puzzles and tensions in cosmology due to a natural desire to better fit the known and newly coming data. At the same…

General Relativity and Quantum Cosmology · Physics 2024-02-06 Alexey Golovnev , Maria-Jose Guzman
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