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Related papers: Anisotropic stress and stability in modified gravi…

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This paper aims to explore some realistic configurations of anisotropic spherical structures in the background of metric $f(R)$ gravity, where $R$ is the Ricci scalar. The solutions obtained by Krori and Barua are used to examine the nature…

General Relativity and Quantum Cosmology · Physics 2017-11-08 Z. Yousaf , M. Sharif , M. Ilyas , M. Z. Bhatti

Anisotropic stress contributions to the gravitational field can arise from magnetic fields, collisionless relativistic particles, hydrodynamic shear viscosity, gravitational waves, skew axion fields in low-energy string cosmologies, or…

Astrophysics · Physics 2009-10-30 John Barrow , Roy Maartens

Certain aspects of three dimensional asymptotically de Sitter spaces are studied, with emphasis on the mapping between gravity observables and the representation of the conformal symmetry of the boundary. In particular, we show that…

High Energy Physics - Theory · Physics 2009-11-07 Bruno Carneiro da Cunha

We investigate the cosmological implications of a new class of modified gravity, where the field equations generically include higher-order derivatives of the matter fields, arising from the introduction of non-dynamical auxiliary fields in…

General Relativity and Quantum Cosmology · Physics 2016-07-01 Tiberiu Harko , Francisco S. N. Lobo , Emmanuel N. Saridakis

We study the implications of $R^n$ extension of Starobinsky model on dynamical instability of Vorticity-free axially symmetric gravitating body. The matter distribution is considered to be anisotropic for which modified field equations are…

General Relativity and Quantum Cosmology · Physics 2015-04-13 Ifra Noureen , Abdul Aziz Bhatti , M. Zubair

We investigate the stability of self-gravitating spherically symmetric anisotropic spheres under radial perturbations. We consider both the Newtonian and the full general-relativistic perturbation treatment. In the general-relativistic…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Krsna Dev , Marcelo Gleiser

We study the Stueckelberg field in de Sitter space, which is a massive vector field with the gauge fixing (GF) term $\frac{1}{2\zeta} (A^\mu\,_{;\, \mu})^2$. We obtain the vacuum stress tensor, which consists of the transverse,…

General Relativity and Quantum Cosmology · Physics 2025-04-15 Yang Zhang , Xuan Ye

Viable models of modified gravity which satisfy both local as well as cosmological tests are investigated. It is demonstrated that some versions of such highly non-linear models exhibit multiply de Sitter universe solutions, which often…

General Relativity and Quantum Cosmology · Physics 2009-02-20 G. Cognola , E. Elizalde , S. D. Odintsov , P. Tretyakov , S. Zerbini

Dynamical analysis of spherically symmetric collapsing star surrounding in locally anisotropic environment with expansion-free condition is presented in $f(R,T)$ gravity, where $R$ corresponds to Ricci scalar and $T$ stands for the trace of…

General Relativity and Quantum Cosmology · Physics 2015-04-21 Ifra Noureen , M. Zubair

One of the possible potential candidates for describing the universe's rapid expansion is modified gravity. In the framework of the modified theory of gravity $f(R,G)$, the present work features the materialization of anisotropic matter,…

General Relativity and Quantum Cosmology · Physics 2022-06-29 W. U. Rahman , M. Ilyas , Z. Yousaf , S. Ullah , F. Khan , R. khan

This paper constructs two immediate extensions of the existing anisotropic solutions in the context of Einstein-Maxwell framework by employing minimal geometric deformation. To achieve this, we assume a static spherical interior initially…

General Relativity and Quantum Cosmology · Physics 2023-10-03 M. Sharif , Tayyab Naseer

The effective anisotropic stress $\eta$ is a key variable in the characterization of many classes of modified gravity theories, as it allows the testing for a long-range force additional to gravity. In this paper we forecast the precision…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Ziad Sakr , Ziyang Zheng , Santiago Casas

We study the metric perturbations in the context of restricted $f(R)$ gravity, in which a parameter for deviation from the full diffeomorphisms of space-time is introduced. We demonstrate that one can choose the parameter to remove the…

General Relativity and Quantum Cosmology · Physics 2016-03-15 Amir Ghalee

We investigate the cosmology of SO(3)-invariant massive gravity with 5 degrees of freedom. In contrast with previous studies, we allow for a non-trivial fiducial metric, which can be justified by invoking, for example, a dilaton-like global…

High Energy Physics - Theory · Physics 2015-06-19 David Langlois , Shinji Mukohyama , Ryo Namba , Atsushi Naruko

In this paper, we investigate complexity of anisotropic cylindrical object under the influence of electromagnetic field in $f(G,T)$ theory, where $G$ and $T$ indicate the Gauss-Bonnet term and trace of the stress-energy tensor,…

General Relativity and Quantum Cosmology · Physics 2023-01-12 M. Sharif , Komal Hassan

This paper uses the definition of complexity for a static spherically symmetric spacetime and extends it to the case of charged distribution. We formulate the Einstein-Maxwell field equations corresponding to the anisotropic interior and…

General Relativity and Quantum Cosmology · Physics 2023-06-02 M. Sharif , Tayyab Naseer

A modified theory of gravity with the function $F(R) = R\exp(\alpha R)$ instead of Ricci scalar $R$ in the Einstein$-$Hilbert action is considered and analyzed. The action of the model is converted into Einstein$-$Hilbert action at small…

General Relativity and Quantum Cosmology · Physics 2013-09-30 S. I. Kruglov

Were studied classical oscillations of background metric in the multidimensional anisotropic model of Kazner in the de-Sitter stage. Obtained dependence of fluctuations on dimension of space-time with infinite expansion. Stability of the…

General Relativity and Quantum Cosmology · Physics 2012-08-01 Sergey Yakovlev

In the model of de Sitter gauge theory of gravity, the empty homogenous and isotropic spacetimes with constant curvature scalar and nonvanishing homogenous and isotropic torsion must have de Sitter metrics. The static de Sitter spacetime…

General Relativity and Quantum Cosmology · Physics 2009-11-05 Chao-Guang Huang , Meng-Sen Ma

This paper deals with existence of strange stars in $f\left(T\right) $ modified gravity. For this purpose, we have taken the diagonal tetrad field of static spacetime with charged anisotropic fluid and MIT bag model, which provide the…

General Physics · Physics 2016-06-28 G. Abbas , Shahid Qaisar , Abdul Jawad