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The actual accelerated expansion of the universe continues being a mystery in physics. Some models had been proposed for this explanations, among them the dark energy, which however has problems of experimental character as well as…

广义相对论与量子宇宙学 · 物理学 2012-11-13 Alejandro Guarnizo

The present research paper is an investigation of dark energy nature of logarithmic $f(R, T)$-gravity cosmology in a flat FLRW space-time universe. We have derived modified Einstein's field equations for the function $f(R, T)=R-16\pi…

广义相对论与量子宇宙学 · 物理学 2023-06-06 Dinesh Chandra Maurya , Jagat Singh , Lalit Kumar Gaur

In this paper, the dynamical system analysis has been performed to analyze the dynamical behavior of the Universe in $f(R,L_m,T)$ gravity with a scalar field. A well motivated potential function and the linear form of the functional…

广义相对论与量子宇宙学 · 物理学 2026-04-21 R. R. Panchal , Divya G. Sanjava , A. H. Hasmani , B. Mishra

We investigate the cosmological reconstruction in modified f(R,T) gravity, where R is the Ricci scalar and T the trace of the stress-energy tensor. Special attention is attached to the case in which the function f is given by f (R, T) = f1…

宇宙学与河外天体物理 · 物理学 2015-05-28 M. J. S. Houndjo

We review the accelerating (mainly, dark energy) cosmologies in modified gravity. Special attention is paid to cosmologies leading to finite-time future singularities in $F(R)$, $F(G)$ and $\mathcal{F}(R,G)$ modified gravities. The removal…

广义相对论与量子宇宙学 · 物理学 2013-02-21 Kazuharu Bamba , Shin'ichi Nojiri , Sergei D. Odintsov

This paper aims to explore some realistic configurations of anisotropic spherical structures in the background of metric $f(R)$ gravity, where $R$ is the Ricci scalar. The solutions obtained by Krori and Barua are used to examine the nature…

广义相对论与量子宇宙学 · 物理学 2017-11-08 Z. Yousaf , M. Sharif , M. Ilyas , M. Z. Bhatti

The present study provides an in-depth analysis of the anisotropic matter distribution and various physical aspects of compact stars in the context of a $f(R,G)$-gravity framework. In order to gain an exhaustive understanding of these…

广义相对论与量子宇宙学 · 物理学 2023-08-22 M. Ilyas , A. R. Athar , F. Khan , Asma Anfal

The present work is an example of the application of the dynamical system analysis in the context of cosmology. Here cosmic evolution is considered in the background of homogeneous and isotropic flat Friedmann-Lema\^{i}tre-Robertson-Walker…

广义相对论与量子宇宙学 · 物理学 2020-11-20 Soumya Chakraborty , Sudip Mishra , Subenoy Chakraborty

We study the late time cosmological evolution of $f(R)$ theories of modified gravity, with the matter content of the universe being that of collisional self interacting matter. We assume that the universe is described by a flat…

广义相对论与量子宇宙学 · 物理学 2015-06-22 V. K. Oikonomou , N. Karagiannakis

Using a perturbative approach we solve stellar structure equations for low-density (solar-type) stars whose interior is described with a polytropic equation of state in scenarios involving a subset of modified gravity theories. Rather than…

太阳与恒星天体物理 · 物理学 2019-02-27 M. Cermeño , J. Carro , A. L. Maroto , M. Ángeles Pérez-García

In this paper, a stable flat cosmological model has been constructed and the evolution of dark energy has been investigated in the framework of the recently suggested $\kappa(R,T)$ gravity. The empirical approach we adopt in the current…

广义相对论与量子宇宙学 · 物理学 2020-02-11 Nasr Ahmed , Anirudh Pradhan

Compact stars have long served as a test bed of gravitational models and their coupling with stellar matter. In this work, we explore the behavior of an exponential model in f(T) gravity through the Tolman-Oppenheimer-Volkoff equation. This…

广义相对论与量子宇宙学 · 物理学 2024-12-30 Gabriel Farrugia , Carlos Gafa' , Jackson Levi Said

Modified gravity is one of the most favorable candidates for explaining the current accelerating expansion of the Universe. In this regard, we study the viability of an alternative gravitational theory, namely $f(R,G)$, by imposing energy…

广义相对论与量子宇宙学 · 物理学 2014-01-30 K. Atazadeh , F. Darabi

In this paper, we examine the acceleration of the Universe's expansion in $F(R,T)$ gravity, where $R$ denotes the Ricci scalar and $T$ the trace of energy-momentum tensor. Indeed, the unknown nature of the source controlling this…

广义相对论与量子宇宙学 · 物理学 2024-04-25 Ahmed Errahmani , Amine Bouali , Safae Dahmani , Imad El Bojaddaini , Taoufik Ouali

In this paper we show how the covariant gauge invariant equations for the evolution of scalar, vector and tensor perturbations for a generic $f(R)$-gravity theory can be recast in order to exploit the power of dynamical system methodology.…

天体物理学 · 物理学 2008-12-12 Sante Carloni , Kishore N. Ananda , Peter K. S. Dunsby , Mohamed E. S. Abdelwahab

In the present paper we generate a set of solutions describing the interior of a compact star under $f(R,T)$ theory of gravity which admits conformal motion. We consider the equation of state (EOS) $p=\omega\rho$ with $0<\omega<1$ for the…

广义相对论与量子宇宙学 · 物理学 2016-12-20 Amit Das , Farook Rahaman , B. K. Guha , Saibal Ray

We study scalar cosmological perturbations in $f(R, T)$ modified gravity theories being $T$ the trace of the energy-momentum tensor. We provide detailed equations for the matter energy density contrast. We solve then numerically to promote…

广义相对论与量子宇宙学 · 物理学 2024-08-28 Jonas Pinheiro da Silva , Hermano Velten

We investigate the Hubble constant tension within $f(R)$ modified gravity in the Jordan frame, focusing on its application to the dynamics of an isotropic Universe. A scalar field, non-minimally coupled to the metric, provides an extra…

广义相对论与量子宇宙学 · 物理学 2024-11-07 Tiziano Schiavone , Giovanni Montani

We use a dynamical system approach to study the cosmological viability of $f(R,\mathcal{G})$ gravity theories. The method consists of formulating the evolution equations as an autonomous system of ODEs, using suitable variables. The…

Recent elaborated by T. Harko and collaborators, the $f(R,T)$ theories of gravity contemplate an optimistic alternative to dark energy, for which $R$ and $T$ stand for the Ricci scalar and the trace of the energy-momentum tensor,…

广义相对论与量子宇宙学 · 物理学 2016-03-23 P. H. R. S. Moraes , J. R. L. Santos