3,321 research outputs found
Anisotropic Universe in Gravity
This paper is devoted to investigate the recently introduced
theory of gravity, where is the
Gauss-Bonnet term, and is the trace of the energy-momentum
tensor. For this purpose, anisotropic background is chosen and a power law
gravity model is used to find the exact solutions
of field equations. In particular, a general solution is obtained which is
further used to reconstruct some important solutions in cosmological contexts.
The physical quantities like energy density, pressure, and equation of state
parameter are calculated. A Starobinsky Like model is
proposed which is used to analyze the behavior of universe for different values
of equation of state parameter. It is concluded that presence of term
in the bivariate function may give
many cosmologically important solutions of the field equations.Comment: 20 pages, 10 figures, minor change
Locally Rotationally Symmetric Bianchi Type Cosmology in Gravity
This manuscript is devoted to investigate Bianchi Type universe in the
context of gravity. For this purpose, we explore the exact solutions
of locally rotationally symmetric Bianchi type spacetime. The modified
field equations are solved by assuming expansion scalar proportional
to shear scalar which gives , where are the metric
coefficients and is an arbitrary constant. In particular, three solutions
have been found and physical quantities are calculated in each case.Comment: 20 Pages, accepted for publication in EPJ
Dissipative Cylindrical Collapse of a Charged Anisotropic Fluid in Gravity
This paper is devoted to investigate the cylindrical collapse of an
anisotropic fluid in gravity. For this purpose, the viscous charged
anisotropic fluid dissipating energy with heat flow and shear is assumed. We
use the perturbation scheme to develop the dynamical equations for the
variables that ultimately lead to the disturbance of the physical variables and
the Starobinksy like model chosen. The evolution of the matter variables
is discussed with the help of these equations. It can be concluded that the
range of dynamic instabilities depends on the field strength, density
distribution, pressure and the curvature term of the model. We find that
our results of Newtonian and post-Newtonian regimes reduce asymptotically to
general relativity solutions in the limiting case.Comment: 20 pages, accepted for publication in Canadian Journal of Physic
Physical Attributes of Anisotropic Compact Stars in Gravity
Modified gravity is one of the potential candidates to explain the
accelerated expansion of the universe. Current study highlights the
materialization of anisotropic compact stars in the context of theory
of gravity. In particular, to gain insight in the physical behavior of three
stars namely, Her , SAX J - and 4U -, energy density,
and radial and tangential pressures are calculated. The gravity model
is split into a Starobinsky like model and a power law model. The
main feature of the work is a -dimensional graphical analysis in which,
anisotropic measurements, energy conditions and stability attributes of these
stars are discussed. It is shown that all three stars behave as usual for
positive values of model parameter .Comment: 21 pages, revised version, to appear in EPJ
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