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Related papers: Anisotropic cosmological solutions in $R + R^2$ gr…

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In the scope of the nonlinear massive gravity, we study fixed points of evolution equations for a Bianchi type--I universe. We find a new attractor solution with non-vanishing anisotropy, on which the physical metric is isotropic but the…

High Energy Physics - Theory · Physics 2012-10-17 A. Emir Gumrukcuoglu , Chunshan Lin , Shinji Mukohyama

We derive transition rules for Kasner exponents in bouncing Bianchi I models with generic perfect fluid matter fields for a broad class of modified gravity theories where cosmological singularities are resolved and replaced by a…

General Relativity and Quantum Cosmology · Physics 2019-12-12 Marco de Cesare , Edward Wilson-Ewing

We consider dynamics of a flat anisotropic Universe filled by a perfect fluid near a cosmological singularity in quadratic gravity. Two possible regimes are described -- the Kasner anisotropic solution and an isotropic "vacuum radiation"…

General Relativity and Quantum Cosmology · Physics 2017-01-04 A. Toporensky , D. Müller

Anisotropic Bianchi-III cosmological model is investigated with variable gravitational and cosmological constants in the framework of Einstein's general relativity. The shear scalar is considered to be proportional to the expansion scalar.…

General Relativity and Quantum Cosmology · Physics 2015-06-23 S. K. Tripathy , D. Behera , T. R. Routray

We analyze the state space of a Bianchi-I universe with anisotropic sources. Here we consider an extended state space which includes null geodesics in this background. The evolution equations for all the state observables are derived.…

General Relativity and Quantum Cosmology · Physics 2016-02-09 Pavan K. Aluri , Sukanta Panda , Manabendra Sharma , Snigdha Thakur

We investigate the behaviour on approach to the initial singularity in higher-order extensions of general relativity by finding exact cosmological solutions for a wide class of models in which the Lagrangian is allowed to depend nonlinearly…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Jonathan Middleton

We study the anisotropic Bianchi type-I cosmological model at late times, taking into account quantum gravitational corrections in the formalism of the exact renormalization group flow of the effective average action for gravity. The…

General Relativity and Quantum Cosmology · Physics 2020-02-24 Rituparna Mandal , Sunandan Gangopadhyay , Amitabha Lahiri

In the present paper we discuss dynamic of anisotropic Bianchi I Universe filled by the perfect fluid in teleparallel $f(T)$-gravity. By using as analytical as numerical approaches we confirm the main results of previous authors such as…

General Relativity and Quantum Cosmology · Physics 2022-04-25 Petr V. Tretyakov

Nonlocal RT gravity has proven effective in explaining the late-time cosmic acceleration while remaining consistent with local gravity tests. However, most previous cosmological studies of this theory have assumed an isotropic background,…

General Relativity and Quantum Cosmology · Physics 2026-03-17 Jiajun Zhou , Shuxun Tian , Zong-Hong Zhu

We investigate the evolution of cosmological anisotropies within the framework of $f\left(G\right)$-gravity. Specifically, we consider a locally rotationally symmetric geometry in four-dimensional spacetime that describes the Bianchi I,…

General Relativity and Quantum Cosmology · Physics 2025-12-25 R. Bogadi , A. Giacomini , M. Govender , C. Hansraj , G. Leon , A. Paliathanasis

We show that it is possible to realize a cosmological bouncing solution in an anisotropic but homogeneous Bianchi-I background in a class of non-local, infinite derivative theories of gravity. We show that the anisotropic shear grows slower…

General Relativity and Quantum Cosmology · Physics 2021-07-20 K. Sravan Kumar , Shubham Maheshwari , Anupam Mazumdar , Jun Peng

The objective of this work enclosed with the study of spatially homogeneous anisotropic Bianchi type-I universe in $f(R,T)$ gravity (where $R$ is the Ricci scalar and $T$ is the trace of stress energy momentum tensor) in two different cases…

General Relativity and Quantum Cosmology · Physics 2017-03-20 P. K. Sahoo , Parbati Sahoo , Binaya K. Bishi

The present work is related to anisotropic cosmological evolution in metric $f(R)$ theory of gravity. The initial part of the paper develops the general cosmological dynamics of homogeneous anisotropic Bianchi-I spacetime in $f(R)$…

General Relativity and Quantum Cosmology · Physics 2019-01-23 Kaushik Bhattacharya , Saikat Chakraborty

In this paper, we study anisotropic universe using Noether symmetries in modified gravity. In particular, we choose locally rotationally symmetric Bianchi type-$I$ universe for the analysis in $f(R,\mathcal{G})$ gravity, where $R$ is the…

General Relativity and Quantum Cosmology · Physics 2017-05-18 M. Farasat Shamir , Fiza Kanwal

We examine homogeneous but anisotropic cosmologies in scalar-tensor gravity theories, including Brans-Dicke gravity. We present a method for deriving solutions for any isotropic perfect fluid with a barotropic equation of state…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Jose P. Mimoso , David Wands

We present an anisotropic cosmological model based on a new exact solution of Einstein equations. The matter content consists of an anisotropic scalar field minimally coupled to gravity and of two isotropic perfect fluids that represent…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Saulo Carneiro , Guillermo A. Mena Marugan

We study the homogeneous and anisotropic evolution of Bianchi type-I spacetime driven by perfect fluid with shear viscosity. We obtain exact solutions by considering the simplest form of the equation of state wherein the pressure and the…

General Relativity and Quantum Cosmology · Physics 2024-07-22 Inyong Cho , Rajibul Shaikh

Despite having the somewhat successful description of accelerated cosmology, the early evolution of the universe always challenges mankind. Our promising approach lies in a new class of symmetric teleparallel theory of gravity named $f(Q)$,…

General Relativity and Quantum Cosmology · Physics 2022-01-25 Avik De , Sanjay Mandal , J. T. Beh , Tee-How Loo , P. K. Sahoo

We study the global dynamical behavior of spatially homogeneous solutions of the Einstein equations in Bianchi type I symmetry, where we use non-tilted elastic matter as an anisotropic matter model that naturally generalizes perfect fluids.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Simone Calogero , J. Mark Heinzle

This paper is devoted to investigate the exact solutions of Bianchi type $I$ spacetime in the context of $f(R,T)$ gravity [1], where $f(R,T)$ is an arbitrary function of Ricci scalar $R$ and trace of the energy momentum tensor $T$. For this…

General Relativity and Quantum Cosmology · Physics 2015-06-30 M. Farasat Shamir