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相关论文: Role of Tilted Congruence and $f(R)$ Gravity on Re…

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We provide a covariant framework to study singularity-free Lema\^itre-Tolman-Bondi spacetimes with effective corrections motivated by loop quantum gravity. We show that, as in general relativity, physically reasonable energy distributions…

广义相对论与量子宇宙学 · 物理学 2024-03-07 Asier Alonso-Bardaji , David Brizuela

This paper is about the $n+2$-dimensional gravitational contraction of inhomogeneous fluid without heat flux in the framework of $f(R)$ metric theory of gravity. Matching conditions for two regions of a star has been derived by using the…

广义相对论与量子宇宙学 · 物理学 2017-08-02 G. Abbas , M. S. Khan , Zahid Ahmad , M. Zubair

We consider spherically symmetric inhomogeneous dust models with a positive cosmological constant, $\Lambda$, given by the Lemaitre-Tolman-Bondi metric. These configurations provide a simple but useful generalization of the Lambda-CDM model…

广义相对论与量子宇宙学 · 物理学 2015-03-14 Roberto A. Sussman , German Izquierdo

We present a systematic analysis of the dynamics of flat Friedmann-Lema\^{i}tre-Robertson-Walker cosmological models with radiation and dust matter in generalized teleparallel $f(T)$ gravity. We show that the cosmological dynamics of this…

广义相对论与量子宇宙学 · 物理学 2017-09-05 Manuel Hohmann , Laur Jarv , Ulbossyn Ualikhanova

We investigate various anisotropic spherical distributions of charged celestial bodies within the context of f(R) gravity, where R represents the Ricci scalar. The properties of specific charged compact objects are analyzed by using the…

广义相对论与量子宇宙学 · 物理学 2025-05-13 W. U. Rahman , M. Ilyas , Yi Zhong , De-Liang Yao

We consider static spherically symmetric self-gravitating configurations of the perfect fluid within the framework of the torsion-based extended theory of gravity. In particular, we use the covariant formulation of $f(T)$ gravity with $f(T)…

广义相对论与量子宇宙学 · 物理学 2018-10-03 Sasa Ilijic , Marko Sossich

We analyze the properties of the tilted Szekeres spacetime, i.e. the version of such spacetime as seen by a congruence of observers with respect to which the fluid is moving. The imperfect fluid and the kinematical variables associated to…

广义相对论与量子宇宙学 · 物理学 2015-06-05 L. Herrera , A. Di Prisco , J. Ibañez , J. Carot

Teleparallel Gravity (TG) describes gravitation as a torsional- rather than curvature-based effect. As in curvature-based constructions of gravity, several different formulations can be proposed, one of which is the Teleparallel equivalent…

广义相对论与量子宇宙学 · 物理学 2020-07-01 Soumya Chakrabarti , Jackson Levi Said

We analyze a modified $f(R)$ theory of gravity in the Palatini formulation, when an Holst term endowed with a dynamical Immirzi field is included. We study the basic features of the model, especially in view of liminating the torsion field…

广义相对论与量子宇宙学 · 物理学 2019-03-27 Flavio Bombacigno , Giovanni Montani

This article reviews an approach for constructing a simple relativistic fractal cosmology whose main aim is to model the observed inhomogeneities of the distribution of galaxies by means of the Lemaitre-Tolman solution of Einstein's field…

宇宙学与河外天体物理 · 物理学 2009-10-27 Marcelo B. Ribeiro

In this study, we investigate a Palatini $f(R)$ gravity model featuring a quadratic term correction, aligning it with the most recent expansion rate data, with a particular focus on the latest SNIa and BAO data. Our analysis employs CC data…

广义相对论与量子宇宙学 · 物理学 2024-01-10 Débora Aguiar Gomes , Rebecca Briffa , Aleksander Kozak , Jackson Levi Said , Margus Saal , Aneta Wojnar

We study the effects that the gravitational interaction of $f(R)$ theories of gravity in Palatini formalism has on the stationary states of the Hydrogen atom. We show that the role of gravity in this system is very important for lagrangians…

广义相对论与量子宇宙学 · 物理学 2008-11-26 Gonzalo J. Olmo

The Boltzmann distribution of an ideal gas is determined by the Hamiltonian function generating single particle dynamics. Systems with higher complexity often exhibit topological constraints, which are independent of the Hamiltonian and may…

广义相对论与量子宇宙学 · 物理学 2021-07-29 Naoki Sato

We use observations related to the variation of fundamental constants, in order to impose constraints on the viable and most used $f(T)$ gravity models. In particular, for the fine-structure constant we use direct measurements obtained by…

广义相对论与量子宇宙学 · 物理学 2017-04-18 Rafael C. Nunes , Alexander Bonilla , Supriya Pan , Emmanuel N. Saridakis

This paper analyses the cosmological consequences of a modified theory of gravity whose action integral is built from a linear combination of the Ricci scalar $R$ and a quadratic term in the covariant derivative of $R$. The resulting…

广义相对论与量子宇宙学 · 物理学 2015-12-31 R. R. Cuzinatto , C. A. M. de Melo , L. G. Medeiros , P. J. Pompeia

In this paper, we investigate irregularities in a cylindrical self-gravitating system which contains the properties of an imperfect matter and electromagnetic field. For $f(R,T,Q)$ theory, in which $R$ represents the Ricci scalar and $T$…

综合物理 · 物理学 2021-08-30 Z. Yousaf , M. Z. Bhatti , T. Naseer , I. Ahmad

A spinning fluid embedded in a space section flat Friedmann model is used to compute the cosmological density perturbation of the model.The spinning fluid obeys the Einstein-Cartan field equations while the Friedmann embedded model is…

天体物理学 · 物理学 2007-05-23 L. C. Garcia de Andrade

We study new FRW type cosmological models of modified gravity treated on the background of Palatini approach. These models are generalization of Einstein gravity by the presence of a scalar field non-minimally coupled to the curvature. The…

广义相对论与量子宇宙学 · 物理学 2012-03-13 A. Borowiec , M. Kamionka , A. Kurek , M. Szydlowski

Using the exact Lemaitre-Bondi-Tolman solution with a non-vanishing cosmological constant $\Lambda$, we investigate how the presence of a local spherically-symmetric inhomogeneity can affect apparent cosmological observables, such as the…

宇宙学与河外天体物理 · 物理学 2015-09-01 Antonio Enea Romano , Misao Sasaki , Alexei A. Starobinsky

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…

综合物理 · 物理学 2018-05-29 Z. Yousaf , M. Zaeem-ul-Haq Bhatti , M. Ilyas