Zobrazeno 1 - 10
of 322
pro vyhledávání: '"Kausar, H."'
Publikováno v:
Phys. Rev. D 93, 124071 (2016)
Many studies have been carried out in the literature to evaluate the number of polarization modes of gravitational waves in modified theories, in particular in $f(R)$ theories. In the latter ones, besides the usual two transverse-traceless tensor mod
Externí odkaz:
http://arxiv.org/abs/1606.07000
Publikováno v:
Eur. Phys. J. Plus (2015) 130: 204
We consider a modified gravity theory, $f(R)=R+\alpha R^n-\frac{\mu^4}{R^m}$, in the metric formulation and analyze the contribution of electromagnetic field on the range of dynamical instability of a star filled with anisotropic matter. The collapse
Externí odkaz:
http://arxiv.org/abs/1510.05514
Autor:
Kausar, H. Rizwana, Noureen, Ifra
This manuscript is devoted to study the combined effect of a viable model, f(R) = R + \alpha R^n, and electromagnetic field on the instability range of gravitational collapse. We assume charged anisotropic fluid that dissipate energy via heat flow an
Externí odkaz:
http://arxiv.org/abs/1401.8085
Autor:
Sharif, M., Kausar, H. Rizwana
Publikováno v:
Astrophys. Space Sci. 337(2012)805-813
We consider a collapsing sphere and discuss its evolution under the vanishing expansion scalar in the framework of $f(R)$ gravity. The fluid is assumed to be locally anisotropic which evolves adiabatically. To study the dynamics of the collapsing flu
Externí odkaz:
http://arxiv.org/abs/1201.2093
Autor:
Sharif, M., Kausar, H. Rizwana
Publikováno v:
JCAP 07(2011)022
Dark energy models based on f(R) theory have been extensively studied in literature to realize the late time acceleration. In this paper, we have chosen a viable f(R) model and discussed its effects on the dynamical instability of expansionfree fluid
Externí odkaz:
http://arxiv.org/abs/1109.3010
Autor:
Sharif, M., Kausar, H. Rizwana
Publikováno v:
Int. J. Mod. Phys. D20(2011) 2239-2252
We consider the modified $f(R)$ theory of gravity whose higher order curvature terms are interpreted as a gravitational fluid or dark source. The gravitational collapse of a spherically symmetric star, made up of locally anisotropic viscous fluid, is
Externí odkaz:
http://arxiv.org/abs/1108.2666
Autor:
Sharif, M., Kausar, H. Rizwana
Publikováno v:
Phys.Lett.B697:1-6,2011
This paper is devoted to study the Bianchi type III model in the presence of anisotropic fluid in f(R) gravity. Exponential and power-law volumetric expansions are used to obtain exact solutions of the field equations. We discuss the physical behavio
Externí odkaz:
http://arxiv.org/abs/1101.3372
Autor:
Sharif, M., Kausar, H. Rizwana
Publikováno v:
Astrophys.Space Sci.332:463-471,2011
In this paper, we solve the field equations in metric f(R) gravity for Bianchi type VI_0 spacetime and discuss evolution of the expanding universe. We find two types of non-vacuum solutions by taking isotropic and anisotropic fluids as the source of
Externí odkaz:
http://arxiv.org/abs/1010.2554
Autor:
Sharif, M., Kausar, H. Rizwana
Publikováno v:
Mod.Phys.Lett.A25:3299-3311,2010
The purpose of this paper is to study the effects of dark energy on dynamics of the collapsing fluid within the framework of metric f(R) gravity. The fluid distribution is assumed to be locally anisotropic and undergoing dissipation in the form of he
Externí odkaz:
http://arxiv.org/abs/1008.2678
Autor:
Sharif, M., Kausar, H. Rizwana
Publikováno v:
Astrophys. Space Sci.331:281-288, 2011
In this paper, we investigate spherically symmetric perfect fluid gravitational collapse in metric $f(R)$ gravity. We take non-static spherically symmetric metric in the interior region and static spherically symmetric metric in the exterior region o
Externí odkaz:
http://arxiv.org/abs/1007.2852