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相关论文: Bouncing solutions in Rastall's theory with a baro…

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In this study, we explore the thermodynamic aspects of a modified version of Rastall's gravity theory and its implications for cosmological scenarios. We analyze the role of non-conserved energy-momentum tensor equations and investigate…

广义相对论与量子宇宙学 · 物理学 2025-12-01 José A. C. Nogales , K. Luz-Burgoa , Laysa G. Martins

Rastall's theory is a generalization of Einstein's equations in which the energy-momentum tensor is not a conserved quantity, its covariant derivative is proportional to the gradient of the Ricci scalar and this fact can be associated with…

广义相对论与量子宇宙学 · 物理学 2015-03-05 A. F. Santos , S. C. Ulhoa

The Rastall's theory is a modification of General Relativity touching one of the cornestone of gravity theory: the conservation laws. In Rastall's theory, the energy-momentum tensor is not conserved anymore, depending now on the gradient of…

广义相对论与量子宇宙学 · 物理学 2015-06-19 J. C. Fabris , O. F. Piattella , D. C. Rodrigues , M. H. Daouda

The basic aim of this manuscript is to investigate the cosmological solutions in the context of the modified $f(R, T)$ theory of gravity, where $R$ is the Ricci scalar and $T$ is the trace of the energy-momentum tensor. For our current…

广义相对论与量子宇宙学 · 物理学 2024-03-26 Adnan Malik , Tayyaba Naz , Aimen Rauf , M. Farasat Shamir , Z. Yousaf

A bouncing universe is a viable candidate to solve the initial singularity problem. Here we consider bouncing solutions in the context of $f(R,\mathcal{G})$ gravity by using an order reduction technique which allows one to find solutions…

广义相对论与量子宇宙学 · 物理学 2020-06-24 Bruno J. Barros , Elsa M. Teixeira , Daniele Vernieri

We investigate the cosmic dynamics of Rastall gravity in non-flat Friedmann-Robertson-Walker (FRW) space-time with barotropic fluid. In this context, we are concerned about the class of model satisfying the affine equation of state. We…

广义相对论与量子宇宙学 · 物理学 2022-07-27 Ashutosh Singh , Gyan Prakash Singh , Anirudh Pradhan

Bouncing non-singular isotropic cosmological solutions are investigated in a simple model of scalar-tensor gravity. New families of such solutions are found and their properties are presented and analyzed using an effective potential as the…

广义相对论与量子宇宙学 · 物理学 2022-01-28 D. Polarski , A. A. Starobinsky , Y. Verbin

This study explores the application of complexity factor within the context of Rastall gravity, exploring its implications on a static spacetime admitting spherical symmetry associated with anisotropic fluids under an electromagnetic field.…

广义相对论与量子宇宙学 · 物理学 2025-08-20 Tayyab Naseer

The present work analyzes the various conditions in which there can be a bouncing universe solution in f(R) gravity. In the article an interesting method, to analyze the bouncing FRW solutions in a spatially flat universe using f(R) gravity…

广义相对论与量子宇宙学 · 物理学 2014-12-09 Niladri Paul , Saikat Nil Chakrabarty , Kaushik Bhattacharya

We investigate stability of the Einstein static solution against homogeneous scalar, vector and tensor perturbations in the context of Rastall theory of gravity. We show that this solution in the presence of perfect fluid and vacuum energy…

广义相对论与量子宇宙学 · 物理学 2018-07-10 F. Darabi , K. Atazadeh , Y. Heydarzade

In this paper, the notion of complexity factor and its implication is extended to the framework of non-conserved Rastall theory of gravity. First of all, the field equations governing a static spherical geometry associated with the…

广义相对论与量子宇宙学 · 物理学 2025-07-11 Tayyab Naseer

Cosmological solutions for covariant canonical gauge theories of gravity are presented. The underlying covariant canonical transformation framework invokes a dynamical space-time Hamiltonian consisting of the Einstein-Hilbert term plus a…

广义相对论与量子宇宙学 · 物理学 2019-06-06 David Benisty , David Vasak , Eduardo Guendelman , Jurgen Struckmeier

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…

广义相对论与量子宇宙学 · 物理学 2025-03-27 Farzad Milani

We construct a Born-Infeld-type $f(R,{\cal G})$ modification of gravity, where ${\cal G}$ is the Gauss-Bonnet term, by embedding Born-Infeld electrodynamics in a five-dimensional pure modified gravity. This method leads to the…

广义相对论与量子宇宙学 · 物理学 2026-04-30 Yermek Aldabergenov , Wei Lin , Rongjian Li , Ding Ding , Yidun Wan

We have investigated some bouncing models in the framework of an extended gravity theory where the usual Ricci scalar in the gravitational action is replaced by a sum of the Ricci scalar and a term proportional to the trace of the energy…

广义相对论与量子宇宙学 · 物理学 2019-05-24 Sunil Kumar Tripathy , Rakesh Kumar Khuntia , Priyabrata Parida

We explore the possibility of realizing a non-singular bounce in the early universe within the framework of modified gravity with spacetime torsion. In Einstein Cartan theory, torsion is embedded in the spacetime by adding an antisymmetric…

广义相对论与量子宇宙学 · 物理学 2026-01-21 Sonej Alam , Somasri Sen , Soumitra Sengupta

In this work we study classical bouncing solutions in the context of $f({\sf R},{\sf T})={\sf R}+h({\sf T})$ gravity in a flat {\sf FLRW} background using a perfect fluid as the only matter content. Our investigation is based on introducing…

广义相对论与量子宇宙学 · 物理学 2018-06-05 Hamid Shabani , Amir Hadi Ziaie

Rastall's theory belongs to the class of non-conservative theories of gravity. In vacuum, the only non-trivial static, spherically symmetric solution is the Schwarzschild one, except in a very special case. When a canonical scalar field is…

广义相对论与量子宇宙学 · 物理学 2017-03-03 K. A. Bronnikov , J. C. Fabris , O. F. Piattella , E. C. Santos

Recent developments in observational cosmology have led to attempts to make modifications on both sides of the Einstein equation to explain some of the puzzling new findings. What follows is an examination of the source of gravity that we…

宇宙学与河外天体物理 · 物理学 2014-01-23 Edward A Spiegel

Rastall's theory is based on the non-conservation of the energy-momentum tensor. We show that, in this theory, if we introduce a two-fluid model, one component representing vacuum energy whereas the other pressureless matter (e.g. baryons…

宇宙学与河外天体物理 · 物理学 2012-04-27 Carlos E. M. Batista , Mahamadou H. Daouda , Júlio C. Fabris , Oliver F. Piattella , Davi C. Rodrigues
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