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Related papers: A numerical analysis for G(t) in a scalar tensor t…

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In this paper we perform the reconstruction scheme of the gravitational action within $f(T,\mathcal{T})$ gravity, where $T$ and $\mathcal{T}$ denote the torsion scalar and the trace of the energy momentum tensor, respectively. We…

General Relativity and Quantum Cosmology · Physics 2016-01-21 S. B. Nassur , M. J. S. Houndjo , A. V. Kpadonou , M. E. Rodrigues , J. Tossa

The present acceleration of the Universe strongly indicated by recent observational data can be modeled in the scope of a scalar-tensor theory of gravity. We show that it is possible to determine the structure of this theory (the scalar…

General Relativity and Quantum Cosmology · Physics 2009-10-31 B. Boisseau , G. Esposito-Farese , D. Polarski , A. A. Starobinsky

The aim of this paper is to reconstruct and analyze the stability of some cosmological models against linear perturbations in $f(\mathcal{G},T)$ gravity ($\mathcal{G}$ and $T$ represent the Gauss-Bonnet invariant and trace of the…

General Relativity and Quantum Cosmology · Physics 2017-06-22 M. Sharif , Ayesha Ikram

The evolution of scale-invariant gravity waves from the early universe is analyzed using an equation of state which smoothly interpolates between the radiation dominated era and the present matter dominated era. We find that for large…

Astrophysics · Physics 2009-10-22 K. -W. Ng , A. D. Speliotopoulos

Unlike general relativity, the scalar gravitational waves can be excited due to the radial oscillations in scalar-tensor gravity. To examine the scalar gravitational waves in scalar-tensor gravity, we derive the evolution equations of the…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Hajime Sotani

The Newtonian approximation with a nonvanishing nonlocal background field is analyzed for the scalar-tensor nonlocal gravity and nonlocal Gauss-Bonnet gravity. For these two theories, our calculations show that the Newtonian gravitational…

General Relativity and Quantum Cosmology · Physics 2019-03-28 S. X. Tian , Zong-Hong Zhu

That preferred-frame theory accounts for special relativity and reduces to it if the gravitation field cancels. Starting from an interpretation of gravity as a pressure force, it is based on just one scalar field. This scalar gives the…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Mayeul Arminjon

The Parametrized Post-Newtonian expansion of gravitational theories with a scalar field coupled to the Gauss-Bonnet invariant is performed and confrontation of such theories with Solar system experiments is discussed.

General Relativity and Quantum Cosmology · Physics 2008-11-26 Thomas P. Sotiriou , Enrico Barausse

We discuss the production and evolution of cosmological gravitons showing how the cosmological background affects their dynamics. Besides, the detection of cosmological gravitons could constitute an extremely important signature to…

General Relativity and Quantum Cosmology · Physics 2017-05-03 Salvatore Capozziello , Mariafelicia De Laurentis , Shin'ichi Nojiri , Sergei D. Odintsov

We investigate the possibility of future singularity due to the accelerating expansion of the Universe. It has been found that the gravitational theory comprises Ricci scalar $R$ and Gauss-Bonnet invariant $\mathcal{G}$, known as…

General Relativity and Quantum Cosmology · Physics 2023-10-18 Santosh V Lohakare , Francisco Tello-Ortiz , B. Mishra , S. K. Tripathy

We study the dynamical description of scalar-tensor gravity by performing the best-fit analysis for two cases of exponential and power-law form of the potential and scalar field function coupled to the curvature. The models are then tested…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Hossein Farajollahi , Amin Salehi , Mohammad Nasiri

In the present paper we take a step towards the generalization of the post-Newtonian formalism to tensor-multi-scalar theories. These are theories where we have more than one scalar field being mediators of the gravitational interaction in…

General Relativity and Quantum Cosmology · Physics 2022-03-24 Oliver Schön , Daniela D. Doneva

In this article, we explore the comprehensive narrative of cosmic evolution within a cosmological framework by utilizing a novel form of gravity known as generalized symmetric teleparallel gravity, denoted as $f(Q,T)$ gravity. Here, $Q$…

General Physics · Physics 2024-09-10 Surajit Das , Sanjay Mandal

Scalar-tensor theories are studied in the context of cosmological evolution, where the expansion history of the Universe is reconstructed. It is considered quintessence/phantom models, where inflation and cosmic acceleration are reproduced.…

High Energy Physics - Theory · Physics 2008-12-11 Diego Sáez-Gómez

The paper deals with cosmology in modified f(T) gravity theory. With some phenomenological choices for the function f(T) it is possible to have cosmological solutions describing different phases of the evolution of the Universe for the…

General Relativity and Quantum Cosmology · Physics 2020-11-03 Akash Bose , Subenoy Chakraborty

We study the quantum evolution of the early universe, its semi-classical analogue together with inflationary regime, in view of a generalized modified theory of gravity. The action is built by supplementing the non-minimally coupled…

High Energy Physics - Theory · Physics 2021-01-11 Ranajit Mandal , Dalia Saha , Mohosin Alam , Abhik Kumar Sanyal

It is accepted by the majority of scientific community that the Universe is currently in an accelerated epoch. In order to explain this shock of late 90's, a lot of dark energy candidates have been proposed. We study in the context of f (R)…

High Energy Physics - Theory · Physics 2014-11-20 Diego Sáez-Gómez

A relativistic theory of modified gravity has been recently proposed by Bekenstein. The tensor field in Einstein's theory of gravity is replaced by a scalar, a vector, and a tensor field which interact in such a way to give Modified…

Astrophysics · Physics 2008-11-26 C. Skordis , D. F. Mota , P. G. Ferreira , C. Boehm

We consider scalar tensor theories of gravity assuming that the scalar field is non minimally coupled with gravity. We use this theory to study evolution of a flat homogeneous and isotropic universe. In this case the dynamical equations can…

Astrophysics · Physics 2012-07-13 M. Demianski , E. Piedipalumbo , C. Rubano , C. Tortora

In this work, we investigate cosmologies where the gravitational constant varies in time, with the aim of explaining the accelerated expansion without a cosmological constant. We achieve this by considering a phenomenological extension to…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-18 Ekim Taylan Hanımeli , Brahim Lamine , Alain Blanchard , Isaac Tutusaus