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In this study, FRW cosmology in modified gravity containing arbitrary function $f(R)$ is taken into consideration when our action are coupled with Weyl tensor. It is indicated that the bouncing solution emerges in the model while the…

General Physics · Physics 2015-03-31 Mohammad Ghanaatian , Farzad Milani

Within the context of modified gravity and dark energy scenarios of the accelerating universe, we study the stability of de Sitter space with respect to inhomogeneous perturbations using a gauge-independent formalism. In modified gravity…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Valerio Faraoni

Conditions for the existence and stability of de Sitter space in modified gravity are derived by considering inhomogeneous perturbations in a gauge-invariant formalism. The stability condition coincides with the corresponding condition for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Valerio Faraoni , Shahn Nadeau

In this study, we explore the dynamics of the universe using a modified gravity model represented by $f(R, G, T)$, where $R$ is the Ricci scalar, $G$ is the Gauss-Bonnet invariant, and $T$ is the trace of the stress-energy tensor. The model…

General Relativity and Quantum Cosmology · Physics 2025-03-27 Farzad Milani

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

In the present paper, we investigate constrained transit cosmological models in the most recent proposed modified gravity theory, $f(R,L_{m},T)$-gravity. We obtain the modified field equations for a flat homogeneous and isotropic…

General Relativity and Quantum Cosmology · Physics 2024-12-20 Dinesh Chandra Maurya

We use a modified Einstein-Maxwell gravity to study stability of an electrostatic spherical star. Correction terms in this model are scalers which are made from contraction of Ricci tensor and electromagnetic vector potential. Our…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Hossein Ghaffarnejad , Tohid Ghorbani , Firoozeh Eidizadeh

We present a thorough stability analysis of modified gravity theories in the presence of matter fields. We use the Effective Field Theory framework for Dark Energy and Modified Gravity to retain a general approach for the gravity sector and…

General Relativity and Quantum Cosmology · Physics 2017-03-14 Antonio De Felice , Noemi Frusciante , Georgios Papadomanolakis

In this paper, we have considered flat Friedmann-Lema\^{i}tre-Robertson-Walker metric in the framework of perfect fluid models and modified $f(G)$ gravity (where $G$ is the Gauss Bonnet invariant). Particularly, we have considered…

General Relativity and Quantum Cosmology · Physics 2017-08-08 Kazuharu Bamba , M. Ilyas , M. Z. Bhatti , Z. Yousaf

A novel function for modified gravity is proposed, $f(R, T)=R+\lambda R^2+2\beta\ln(T)$, with constants $\lambda$ and $\beta$, scalar curvature $R$, and the trace of stress energy tensor $T$, satisfying $T=\rho-3p>0$. Subsequently, two…

General Physics · Physics 2020-06-16 Emilio Elizalde , Nisha Godani , Gauranga C. Samanta

In this paper, we have investigated the physical behavior of cosmological models in the framework of modified Teleparallel gravity. This model is established using a Renyi holographic ``dark energy model (RHDE) with a Hubble cutoff. Here we…

General Relativity and Quantum Cosmology · Physics 2023-01-11 Vinod Kumar Bhardwaj , Archana Dixit , Anirudh Pradhan , Symala Krishannair

We study FRW cosmology for a double scalar - tensor theory of gravity where two scalar fields are nonminimally coupled to the geometry. In a framework to study stability and attractor solutions of the model in the phase space, we constraint…

General Physics · Physics 2015-06-03 H. Farajollahi , A. Shahabi , A. Salehi

In this paper, we study $F(R)$ gravity by Hu-Sawicki model in Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) background. The Friedmann equations are calculated by modified gravity action, and then the obtained Friedmann equations are…

General Relativity and Quantum Cosmology · Physics 2016-05-25 Ali R. Amani

In this paper, we have studied the dynamical aspects of the cosmological model of the Universe in the Weyl type $f(Q,T)$ gravity, which is an extension of symmetric teleparallel gravity. The non-metricity scalar $Q$ has been expressed in…

General Relativity and Quantum Cosmology · Physics 2023-06-02 Rahul Bhagat , S. A. Narawade , B. Mishra

This paper is devoted to examining cosmological bouncing scenarios in the framework of the recently proposed symmetric teleparallel gravity (or $f(Q)$ gravity), where the non-metricity scalar $Q$ represents the gravitational interaction. We…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-17 M. Koussour , N. Myrzakulov

The discovery of apparent cosmological acceleration has spawned a huge number of dark energy and modified gravity theories. The f(R) models of gravity are obtained when one replaces the Ricci scalar in the Einstein-Hilbert action by an…

General Relativity and Quantum Cosmology · Physics 2016-02-08 Boris Bolliet , Richard A. Battye , Jonathan A. Pearson

In this article, the bulk viscosity is introduced in a modified gravity model. The gravitational action has a general $f(R,T)$ form, where $R$ and $ T $ are the curvature scalar and the trace of energy momentum tensor respectively. An…

General Relativity and Quantum Cosmology · Physics 2020-10-02 Simran Arora , Xin-he Meng , S. K. J. Pacif , P. K. Sahoo

In this paper, working in a Friedman-Lemaitre-Robertson-Walker (FLRW), first, in the flat case, we recover the generalized Friedman equation of Quantum Loop cosmology, and therefore the cosmological bounce, in the framework of modified…

General Relativity and Quantum Cosmology · Physics 2021-01-20 Alessandro Casalino , Bruno Sanna , Lorenzo Sebastiani , Sergio Zerbini

In this paper we consider FRW cosmology in modified gravity which contain arbitrary functions $f(\phi)$. It is shown that the bouncing solution appears in the model whereas the equation of state (EoS) parameter crosses the phantom divider.…

General Relativity and Quantum Cosmology · Physics 2011-06-09 H. Farajollahi , F. 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
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