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Related papers: Modified Gauss-Bonnet Gravity with Radiating Fluid…

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In this paper, we consider the effect of electromagnetic field to the definition of complexity in the context of $f(G,T)$ gravity, where $G$ and $T$ express the Gauss-Bonnet term and energy-momentum tensor, respectively. The physical…

General Relativity and Quantum Cosmology · Physics 2023-06-14 M. Sharif , K. Hassan

We investigate cosmological perturbations of f(G) gravity in the presence of a scalar field. Using the 1 + 3 covariant formalism, we present the energy overdensity perturbation equations responsible for large scale structure formation.…

General Relativity and Quantum Cosmology · Physics 2023-12-27 Albert Munyeshyaka , Joseph Ntahompagaze , Tom Mutabazi , Manasse. R Mbonye

In this work, we use reconstruction methods to obtain cosmological solutions in the recently developed scalar-tensor representation of $f(R,T)$ gravity. Assuming that matter is described by an isotropic perfect fluid and the spacetime is…

General Relativity and Quantum Cosmology · Physics 2022-03-15 Tiago B. Gonçalves , João Luís Rosa , Francisco S. N. Lobo

We study a theory of gravity of the form $f(\mathcal{G})$ where $\mathcal{G}$ is the Gauss-Bonnet topological invariant without considering the standard Einstein-Hilbert term as common in the literature, in arbitrary $(d+1)$ dimensions. The…

General Relativity and Quantum Cosmology · Physics 2020-01-30 Francesco Bajardi , Konstantinos F. Dialektopoulos , Salvatore Capozziello

This article focuses on the formulation of some scalar factors which are uniquely expressed in terms of matter variables for dynamical charged dissipative cylindrical geometry in a standard gravity model $\mathcal{R}+\Phi\mathcal{Q}$…

General Relativity and Quantum Cosmology · Physics 2022-09-05 M. Sharif , Tayyab Naseer

The present paper is devoted to investigate the possible emergence of relativistic compact stellar objects through modified $f(R,T)$ gravity. For anisotropic matter distribution, we used Krori and Barura solutions and two notable and viable…

General Physics · Physics 2018-05-29 Z. Yousaf , M. Zaeem-ul-Haq Bhatti , M. Ilyas

The cosmological scalar perturbations of standard matter are investigated in the context of extended teleparallel $f(T)$ gravity theories using the $1+3$ covariant formalism. After a review of the background, gravitational field equations…

General Relativity and Quantum Cosmology · Physics 2020-06-24 Shambel Sahlu , Joseph Ntahompagaze , Amare Abebe , Alvaro de la Cruz-Dombriz , David F. Mota

In $f(T)$ gravity, the theory modifies the gravitational action by introducing a function of the torsion scalar $T$. This approach allows for a different treatment of gravity than general relativity, particularly in cosmological contexts.…

General Relativity and Quantum Cosmology · Physics 2024-10-08 S. Davood Sadatian , S. Mohamad Reza Hosseini

We investigate the propagation of scalar waves induced by matter sources in the context of scalar-tensor theories of gravity which include screening mechanisms for the scalar degree of freedom. The usual approach when studying these…

General Relativity and Quantum Cosmology · Physics 2016-02-24 Jan Ø. Lindroos , Claudio Llinares , David F. Mota

We study the gravitational waves in modified Gauss-Bonnet gravity. Applying the metric perturbation around a cosmological background, we obtain explicit expressions for the wave equations. It is shown that the speed of the traceless mode is…

General Relativity and Quantum Cosmology · Physics 2020-08-25 Tomohiro Inagaki , Masahiko Taniguchi

The objective of this research is to explore compact celestial objects while considering the framework of an extended gravitational theory known as $\mathcal{R}+f(\mathcal{G})$ gravity. The notations $\mathcal{R}$ and $\mathcal{G}$ denote…

General Relativity and Quantum Cosmology · Physics 2024-07-08 G. G. L. Nashed , Kazuharu Bamba

A covariant scalar-tensor-vector gravity theory is developed which allows the gravitational constant $G$, a vector field coupling $\omega$ and the vector field mass $\mu$ to vary with space and time. The equations of motion for a test…

General Relativity and Quantum Cosmology · Physics 2021-11-22 J. W. Moffat

In considering alternative higher-order gravity theories, one is liable to be motivated in pursuing models consistent and inspired by several candidates of a fundamental theory of quantum gravity. Indeed, motivations from string/M-theory…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Nadiezhda Montelongo García , Tiberiu Harko , Francisco S. N. Lobo , José P. Mimoso

This paper discusses the gravitational collapse of dynamical self-gravitating fluid distribution in $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where $\mathcal{Q}=\mathcal{R}_{\varphi\vartheta}\mathcal{T}^{\varphi\vartheta}$. In this…

General Relativity and Quantum Cosmology · Physics 2024-01-11 M. Sharif , Tayyab Naseer

The curvature invariants have been subject of interest due to the debate concerning the notions of intrinsic/extrinsic frame-dragging, the use of the electromagnetic analogy in such classification, and the question of whether there is a…

General Relativity and Quantum Cosmology · Physics 2021-10-26 L. Filipe O. Costa , Lode Wylleman , José Natário

In this paper we consider scalar-tensor theories, allowing for both conformal and disformal couplings to a fluid with a generic equation of state. We derive the effective coupling for both background cosmology and for perturbations in that…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 C. van de Bruck , G. Sculthorpe

We discuss the gravitational collapse of spherical compact objects in the background of $f(R,T,Q)$ theory, where $R$ represent the Ricci scalar, $T$ is the trace of energy momentum tensor while $Q\equiv R_{\mu\nu}T^{\mu\nu}$, and…

General Relativity and Quantum Cosmology · Physics 2020-03-03 M. Z. Bhatti , Kazuharu Bamba , Z. Yousaf , M. Nawaz

In this paper, I consider a $f(R, G, T)$ modified gravity model where $R$ represents the Ricci scalar, $G$ denotes the Gauss-Bonnet invariant, and $T$ signifies the trace of the stress-energy tensor. This model is coupled with two distinct…

General Relativity and Quantum Cosmology · Physics 2024-09-04 Farzad Milani

We investigate the evolution of non vacuum Friedmann-Lema\^itre-Robertson-Walker (FLRW) with any spatial curvature in the context of Gauss-Bonnet gravity. The analysis employs a new method which enables us to explore the phase space of any…

General Relativity and Quantum Cosmology · Physics 2017-09-13 Sante Carloni , José P. Mimoso

We investigate $\eta/s$ in linear scalar fields modified Gauss-Bonnet theory that breaks translation invariance. We first calculate $\eta/s$ both analytically and numerically and show its relationship with temperature in log-log plot. Our…

High Energy Physics - Theory · Physics 2016-09-28 Yi-Li Wang , Xian-Hui Ge