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相关论文: Dynamics of the anisotropic Kantowsky-Sachs geomet…

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We consider a particular example of dynamical compactification of an anisotropic 7+1 dimensional Universe in Einstein - Gauss - Bonnet gravity. Starting from rather general totally anisotropic initial conditions a Universe in question…

广义相对论与量子宇宙学 · 物理学 2020-04-02 Dmitry Chirkov , Alex Giacomini , Alexey Toporensky

We consider the introduction of anisotropy in a class of bouncing models of cosmology. The presence of anisotropy often spells doom on bouncing models, since the energy density due to the anisotropic stress outweighs that of other matter…

广义相对论与量子宇宙学 · 物理学 2022-01-27 Karthik Rajeev , Vikramaditya Mondal , Sumanta Chakraborty

This paper explores exact cosmological solutions of anisotropic universe model through Noether symmetry technique in energy-momentum squared gravity. This theory resolves the primordial singularity and provides viable cosmological…

广义相对论与量子宇宙学 · 物理学 2023-05-24 M. Sharif , M. Zeeshan Gul

To systematically analyze the dynamical implications of the matter content in cosmology, we generalize earlier dynamical systems approaches so that perfect fluids with a general barotropic equation of state can be treated. We focus on…

广义相对论与量子宇宙学 · 物理学 2009-11-10 J. Mark Heinzle , N. Rohr , C. Uggla

In this work we try to understand the late time acceleration of the universe by assuming some modification in the geometry of the space and using dynamical system analysis. This technique allows to understand the behavior of the universe…

广义相对论与量子宇宙学 · 物理学 2021-11-18 Parth Shah , Gauranga C. Samanta

A new cosmological solution of the gravitational field equations in the generalized Randall-Sundrum model for an anisotropic brane with Bianchi I geometry and with perfect fluid as matter sources is presented. The matter is described by a…

广义相对论与量子宇宙学 · 物理学 2009-11-07 Bikash Chandra Paul

We propose a class of theories that can limit scalars constructed from the extrinsic curvature. Applied to cosmology, this framework allows us to control not only the Hubble parameter but also anisotropies without the problem of…

广义相对论与量子宇宙学 · 物理学 2020-10-06 Yuki Sakakihara , Daisuke Yoshida , Kazufumi Takahashi , Jerome Quintin

We give the equations governing the shear evolution in Bianchi spacetimes for general f(R)-theories of gravity. We consider the case of R^n-gravity and perform a detailed analysis of the dynamics in Bianchi I cosmologies which exhibit local…

广义相对论与量子宇宙学 · 物理学 2010-11-05 Jannie A Leach , Sante Carloni , Peter K S Dunsby

We show that in tilting perfect fluid cosmological models with an ultra-radiative equation of state, generically the tilt becomes extreme at late times and, as the tilt instability sets in, observers moving with the tilting fluid will…

广义相对论与量子宇宙学 · 物理学 2009-11-11 A. A. Coley , S. Hervik , W. C. Lim

The homogeneous and isotropic radiation dominated universe, following the inflationary stage, is expressed as a spherically symmetric and inhomogeneous spacetime upon a power law type conformal transformation of the null (cosmological)…

广义相对论与量子宇宙学 · 物理学 2018-05-24 Sujoy K. Modak

In this paper, we investigate and analyze the cosmological dynamics of the universe, with an effect of modified $f(R)$ gravity emerging at cosmological scale. We choose the Einstein frame as a physical frame. We consider phase portraits of…

天体物理学 · 物理学 2007-05-23 Daris Samart

In this paper we analyze the asymptotic behavior of Cardassian cosmological models filled with a perfect fluid and a scalar field with an exponential potential. Cardassian cosmologies arise from modifications of the Friedmann equation, and…

天体物理学 · 物理学 2016-08-30 Ruth Lazkoz , Genly Leon

We show the existence of spatially homogeneous but anisotropic cosmological models whose cosmic microwave background temperature is exactly isotropic at one instant of time but whose rate of expansion is highly anisotropic. The existence of…

广义相对论与量子宇宙学 · 物理学 2009-10-31 W C Lim , U S Nilsson , J Wainwright

We consider an evolution of anisotropic cosmological model on the example of the Bianchi type I homogeneous universe. It is filled by the mixture of matter and dark energy with an arbitrary barotropic equation of state (EoS). The general…

广义相对论与量子宇宙学 · 物理学 2023-06-14 S L Parnovsky

Recent released Planck data and other astronomical observations show that the universe may be anisotropic on large scales. Inspired by this, anisotropic cosmological models have been proposed. We note that the Finsler-Randers spacetime…

宇宙学与河外天体物理 · 物理学 2014-03-25 Zhe Chang , Xin Li , Hai-Nan Lin , Sai Wang

In the Bianchi I cosmology some subclasses of the Horndeski theory allow for the non-standard anisotropy behavior. For example, the anisotropy is damped near the initial singularity instead of tending to infinity. In this article, we…

广义相对论与量子宇宙学 · 物理学 2022-12-27 Ruslan K. Muharlyamov , Tatiana N. Pankratyeva

Under the premise that the current observations of the cosmic microwave background radiation set a very stringent limit to the anisotropy of the universe, we consider an anistropic model in the presence of a barotropic perfect fluid and a…

广义相对论与量子宇宙学 · 物理学 2020-06-02 J. Socorro , S. Pérez-Payán , Abraham Espinoza-García , Luis Rey Díaz-Barrón

We investigate quantum cosmological models in an n-dimensional anisotropic universe in the presence of a massless scalar field. Our basic inspiration comes from Chodos and Detweiler's classical model which predicts an interesting behaviour…

广义相对论与量子宇宙学 · 物理学 2018-02-14 F. A. P. Alves-Júnior , M. L. Pucheu , A. B. Barreto , C. Romero

Chaplygin anisotropic matter governing the cosmological evolution in two identical universes with an intermediate static spherically symmetric region is considered. The static region contains a wormhole allowing one to pass etween two…

广义相对论与量子宇宙学 · 物理学 2013-08-07 Anna Mokeeva , Vladimir Popov

We investigate the dynamics of the spatially flat universes submitted to isotropic tidal forces and adiabatic expansion under Einstein's equations. Surprisingly, the tendency to a high Hubble anisotropy at late times starts to appear as far…

广义相对论与量子宇宙学 · 物理学 2022-07-20 Fabio Scalco Dias , Leandro Gustavo Gomes , Luis Fernando Mello