Effects of some physical factors on the inhomogeneity in planar symmetry

2014 ◽  
Vol 29 (18) ◽  
pp. 1450094 ◽  
Author(s):  
M. Sharif ◽  
M. Zaeem Ul Haq Bhatti
Keyword(s):  
Weyl Tensor ◽  
Anisotropic Fluid ◽  
Physical Factors ◽  
Relativistic Fluids ◽  
Dynamical Equations ◽  
Local Anisotropy ◽  
Structure Scalars ◽  
Energy Density Inhomogeneity ◽  
Planar Symmetry ◽  
Inhomogeneity Factor

This paper is devoted to identify some physical causes of energy density inhomogeneity and stability of self-gravitating relativistic fluids in plane symmetry such as Weyl tensor, local anisotropy, dissipative terms and their specific combination. We first develop a relationship between matter variables and the Weyl tensor and then formulate dynamical equations using Bianchi identities. For the non-dissipative dust fluid, we conclude that the system will remain homogeneous if and only if it is conformally flat which implies the shear-free condition. However, the converse is not true for the non-dissipative isotropic fluid. For non-dissipative anisotropic fluid, the inhomogeneity factor is identified to be one of the structure scalars. A particular case of geodesic with dissipation is also discussed.

Spherically symmetric spacetime with radiating fluids in f(𝒢, T) gravity

2019 ◽  
Vol 34 (27) ◽  
pp. 1950215 ◽  
Author(s):  
M. Farasat Shamir ◽  
Nabeeha Uzair
Keyword(s):  
Weyl Tensor ◽  
Energy Momentum Tensor ◽  
Stellar System ◽  
Momentum Tensor ◽  
Anisotropic Fluid ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Radiating Fluids ◽  
Inhomogeneity Factor ◽  
Symmetric Spacetime

The aim of this paper is to examine the irregularity factors of a self-gravitating stellar system in the existence of anisotropic fluid. We investigate the dynamics of field equations within [Formula: see text] background, where [Formula: see text] is the Gauss–Bonnet invariant and [Formula: see text] is the trace of the energy–momentum tensor. Moreover, we have investigated two differential equations using the conservation law and the Weyl tensor. We have determined the irregularity factors of spherical stellar system for some specific conditions of anisotropic and isotropic fluids, dust, radiating and non-radiating systems in [Formula: see text] gravity. It has been noted that the dissipative matter results in anisotropic stresses and makes the system more complex. The inhomogeneity factor is correlated to one of the scalar functions.

Complexity analysis of dynamical spherically-symmetric dissipative self-gravitating objects in modified gravity

2020 ◽  
Vol 29 (02) ◽  
pp. 2050014
Author(s):  
M. Zubair ◽  
Hina Azmat
Keyword(s):  
Complexity Analysis ◽  
Fluid Distribution ◽  
Anisotropic Fluid ◽  
Spherically Symmetric ◽  
Evolutionary Patterns ◽  
Structure Scalars ◽  
Pressure Anisotropy ◽  
Energy Density Inhomogeneity ◽  
Expansion Condition ◽  
Definition Of

In this paper, we have worked on the concept of complexity factor for nonstatic spherically-symmetric self-gravitating source filled with anisotropic fluid distribution in [Formula: see text] gravity theory. The definition of complexity for dynamical sources, proposed by Herrera, is examined in the framework of [Formula: see text] gravity. We intended to analyze the behavior of complexity factor in modified theory. For this, we defined the scalar functions through orthogonal splitting of Reimann tensor in [Formula: see text] gravity and worked out the structure scalars. We considered the structure scalar [Formula: see text] as a complexity factor to evaluate the complexity of the structure of dynamical system and also to analyze the complexity of the evolutionary patterns of the system under consideration. We took into account the homologous condition and homogeneous expansion condition in order to present the simplest mode of evolution, and found that homologous evolution is the simplest one. We considered both dissipative and nondissipative cases and found that shearing behavior of the fluid is not the same in both cases, however it remained geodesic in both cases. In the end, we established the results for the vanishing of the complexity factor. It has been found that zero complexity condition is satisfied if the energy density inhomogeneity and pressure anisotropy of the fluid configuration cancel each other.

Electromagnetic effects on the inhomogeneity of planar symmetry

2014 ◽  
Vol 29 (26) ◽  
pp. 1450129 ◽  
Author(s):  
M. Sharif ◽  
M. Zaeem Ul Haq Bhatti
Keyword(s):  
Energy Density ◽  
Evolution Equations ◽  
Anisotropic Pressure ◽  
Plane Symmetric ◽  
Anisotropic Matter ◽  
Maxwell Field Equation ◽  
Dissipative Case ◽  
Energy Density Inhomogeneity ◽  
Planar Symmetry ◽  
Inhomogeneity Factor

In this work, we aim to identify the effects of electromagnetic field on the energy density inhomogeneity in self-gravitating plane symmetric spacetime filled with imperfect matter in terms of dissipation and anisotropic pressure. We formulate the Einstein–Maxwell field equation, conservation laws, evolution equations for the Weyl tensor and the transport equation for diffusion approximation. Inhomogeneity factors are identified for some particular cases of non-dissipative and dissipative fluids. For non-dissipative case, we analyze the inhomogeneity factor for dust, isotropic and anisotropic matter distributions while dissipative matter distribution includes the inhomogeneity factor only for geodesic dust fluid. We conclude that electric charge increases the inhomogeneity in the energy density which is due to shear, anisotropy and dissipation.

scholarly journals Influence of modification of gravity on the complexity factor of static spherical structures

2020 ◽  
Vol 495 (4) ◽  
pp. 4334-4346
Author(s):  
Z Yousaf ◽  
Maxim Yu Khlopov ◽  
M Z Bhatti ◽  
T Naseer
Keyword(s):  
Gravitational Theory ◽  
Momentum Tensor ◽  
Matter Distribution ◽  
Field Equations ◽  
Riemann Curvature Tensor ◽  
Structure Scalars ◽  
Pressure Anisotropy ◽  
Spherical Structures ◽  
Energy Density Inhomogeneity ◽  
Definition Of

ABSTRACT The aim of this paper is to generalize the definition of complexity for the static self-gravitating structure in f (R, T, Q) gravitational theory, where R is the Ricci scalar, T is the trace part of energy–momentum tensor, and Q ≡ RαβT αβ. In this context, we have considered locally anisotropic spherical matter distribution and calculated field equations and conservation laws. After the orthogonal splitting of the Riemann curvature tensor, we found the corresponding complexity factor with the help of structure scalars. It is seen that the system may have zero complexity factor if the effects of energy density inhomogeneity and pressure anisotropy cancel the effects of each other. All of our results reduce to general relativity on assuming f (R, T, Q) = R condition.

Cylindrically symmetric relativistic fluids and the purely electric Weyl tensor

2015 ◽  
Vol 12 (10) ◽  
pp. 1550103 ◽  
Author(s):  
Rajesh Kumar ◽  
S. K. Srivastava ◽  
V. C. Srivastava
Keyword(s):  
General Relativity ◽  
Energy Density ◽  
Weyl Tensor ◽  
Einstein’S Equations ◽  
Relativistic Fluids ◽  
Einstein's Equations ◽  
Cylindrically Symmetric ◽  
Expansion Scalar

In General Relativity (GR), the analysis of electric and magnetic Weyl tensors has been studied by various authors. The present study deals with cylindrically symmetric relativistic fluids in GR characterized by the vanishing of magnetic Weyl tensor-purely electric (PE) fields. A very new assumption has been adapted to solve the Einstein's equations and the obtained solution is shearing at all. We signified the importance of PE fields in the context of expansion scalar, energy density, shear and acceleration.

Tolman mass of spherical fluids with electromagnetic field

2019 ◽  
Vol 34 (02) ◽  
pp. 1950012 ◽  
Author(s):  
M. Z. Bhatti ◽  
Z. Yousaf ◽  
A. Yousaf
Keyword(s):  
Gravitational Collapse ◽  
Mass Function ◽  
Physical Factors ◽  
Field Equations ◽  
Density Inhomogeneity ◽  
Local Anisotropy ◽  
Anisotropic Matter ◽  
Weyl Curvature Tensor ◽  
The Impact

Assuming a system with spherical symmetry in f(R) gravity filled with dissipative charged and anisotropic matter, we study the impact of density inhomogeneity and local anisotropy on the gravitational collapse in the presence of charge. For this purpose, we evaluated the modified Maxwell field equations, Weyl curvature tensor, and the mass function. Using Misner–Sharp mass formalism, we construct a relation between the Weyl tensor, density inhomogeneity, and local anisotropy. Specifically, we obtain the expression of modified Tolman mass which helps to analyze the influence of charge and dark source terms on different physical factors, also it helps to study the role of these factors on gravitational collapse.

Complexity factors for static anisotropic axially symmetric fluid distributions in f(R) gravity

2020 ◽  
Vol 17 (03) ◽  
pp. 2050043
Author(s):  
G. Abbas ◽  
H. Nazar
Keyword(s):  
Energy Density ◽  
General Theory ◽  
Graphical Analysis ◽  
Fluid Distribution ◽  
Anisotropic Fluid ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Axially Symmetric ◽  
Structure Scalars ◽  
Isotropic Pressure

In this paper, we have analyzed the complexity factor for the most general axially symmetric static anisotropic fluid distributions in context of [Formula: see text] theory of gravity. For this purpose, we have studied three distinct complexity factors that are organized in terms of three scalar variables (structure scalars) comes from the orthogonal splitting of the curvature tensor. The vanishing of all complexity factors condition for what we choose the simplest fluid distribution that in which system having energy density is homogeneous with isotropic pressure. Although, it has been found that the complexity factors condition can also vanish when inhomogeneous energy density and anisotropy of the pressure cancel each other. Next, we express a class of exact solutions and their graphical analysis as compatible to our models that satisfies the vanishing condition of complexity factors. Finally, it is worth mentioning that these results can reproduce the results of General theory of Relativity under some constraints.

scholarly journals Expansion-free cylindrically symmetric models

2012 ◽  
Vol 90 (9) ◽  
pp. 865-870 ◽  
Author(s):  
M. Sharif ◽  
Z. Yousaf
Keyword(s):  
Energy Density ◽  
Weyl Tensor ◽  
Thin Shell ◽  
Fluid Distribution ◽  
Anisotropic Fluid ◽  
Junction Condition ◽  
Free Condition ◽  
Cylindrically Symmetric ◽  
Vacuum Cavity ◽  
Boundary Surfaces

This paper investigates cylindrically symmetric distribution of an anisotropic fluid under the expansion-free condition, which requires the existence of a vacuum cavity within the fluid distribution. We have discussed two families of solutions that further provide two exact models in each family. Some of these solutions satisfy the Darmois junction condition while some show the presence of a thin shell on both boundary surfaces. We also formulate a relation between the Weyl tensor and energy density.

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