Physics of the Dark Universe, Volume 17, Pages 52-62 , 01/09/2017
Cosmological dynamics of magnetic Bianchi I in viable f(R) models of gravity
Abstract
Standard dynamical system analysis of Einstein–Maxwell equation in f(R) theories is considered in this work. We investigate cosmological dynamics of a uniform magnetic field in the Orthogonal Spatially Homogeneous (OSH) Bianchi I universe with viable f(R) models of gravity. In this work, the f(R)=R−αR<sup>n</sup> and f(R)=R<sup>b</sup>−Λ<sup>c</sup> models are examined by using our dynamical system analysis. Our results show that both of two f(R) models have a viable cosmological consequence identical to the analysis present in Amendola and Tsujikawa (2008) for the FLRW background. Contrary to Amendola and Tsujikawa (2008), we discover in our models that there is an additional anisotropic and non-zero cosmological magnetic fields fixed point emerging before the present of the standard matter epoch. This means that the universe has initially isotropic stage with the intermediated epoch as the anisotropic background and it ends up with the isotropic late-time acceleration. The primordial magnetic fields play a crucial role of the shear evolutions obtained from these two models which have the same scaling of the cosmic time as σ∼t[Formula presented], instead of σ∼t<sup>−1</sup> for the absence of the primordial magnetic cases.
Document Type
Article
Source Type
Journal
Keywords
Cosmic acceleration and its alternative explanationsModels and theoretical properties of vacuum energyModified gravity
ASJC Subject Area
Physics and Astronomy : Astronomy and AstrophysicsEarth and Planetary Sciences : Space and Planetary Science
Funding Agency
Office of the Higher Education Commission