Evolution of expansion-free spherically symmetric self-gravitating non-dissipative fluids and some analytical solutions

2018 ◽  
Vol 15 (04) ◽  
pp. 1850058 ◽  
Author(s):  
Rajesh Kumar ◽  
Sudhir Kumar Srivastava
Keyword(s):  
Analytical Models ◽  
Fluid Distribution ◽  
Junction Condition ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Minkowski Space Time ◽  
Spherically Symmetric Metric ◽  
Anisotropic Fluids ◽  
Vacuum Cavity ◽  
Dissipative Fluids

We consider the distribution of spherically symmetric self-gravitating non-dissipative (but anisotropic) fluids under the expansion-free condition which requires the existence of vacuum cavity within the fluid distribution. The Darmois junction condition is investigated for matching the spherically symmetric metric to an internal vacuum cavity (Minkowski space-time). We have studied some analytical models, total of three family of solutions out of which two satisfy the junction conditions over both the hypersurfaces. The models are investigated under some known dynamical assumptions which further provide analytical solution in each family.

scholarly journals EXPANSION-FREE CAVITY EVOLUTION: SOME EXACT ANALYTICAL MODELS

2011 ◽  
Vol 20 (12) ◽  
pp. 2351-2367 ◽  
Author(s):  
A. DI PRISCO ◽  
L. HERRERA ◽  
J. OSPINO ◽  
N. O. SANTOS ◽  
V. M. VIÑA-CERVANTES
Keyword(s):  
Analytical Models ◽  
Fluid Distribution ◽  
Expansion Scalar ◽  
Kinematical Condition ◽  
Cavity Evolution ◽  
Central Explosion ◽  
Anisotropic Fluids ◽  
Surrounding Fluid ◽  
Vacuum Cavity ◽  
Boundary Surfaces

We consider spherically symmetric distributions of anisotropic fluids with a central vacuum cavity, evolving under the condition of vanishing expansion scalar. Some analytical solutions are found satisfying Darmois junction conditions on both delimiting boundary surfaces, while some others require the presence of thin shells on either (or both) boundary surfaces. The solutions here obtained model the evolution of the vacuum cavity and the surrounding fluid distribution, emerging after a central explosion, thereby showing the potential of expansion–free condition for the study of that kind of problems. This study complements a previously published work where modeling of the evolution of such kind of systems was achieved through a different kinematical condition.

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.

scholarly journals A Note on the Transformability of Spherically Symmetric Metrics

1953 ◽  
Vol 9 (1) ◽  
pp. 13-16 ◽  
Author(s):  
Paul Kustaanheimo
Keyword(s):  
Spherically Symmetric ◽  
Symmetric Metrics ◽  
Spherically Symmetric Metric

SummaryIt is shown that every spherically symmetric metric can be transformed into the isotropic form. As illustration an example is given.

scholarly journals Spherically symmetric dissipative anisotropic fluids: A general study

2004 ◽  
Vol 69 (8) ◽  
Author(s):  
L. Herrera ◽  
A. Di Prisco ◽  
J. Martin ◽  
J. Ospino ◽  
N. O. Santos ◽  
...  
Keyword(s):  
Spherically Symmetric ◽  
General Study ◽  
Anisotropic Fluids

Equivalence principle for charged bodies in a theory of gravitation

1981 ◽  
Vol 59 (11) ◽  
pp. 1730-1733 ◽  
Author(s):  
R. B. Mann ◽  
J. W. Moffat
Keyword(s):  
Equivalence Principle ◽  
Maxwell Equations ◽  
Test Body ◽  
Spherically Symmetric ◽  
Point Particles ◽  
Symmetric Field ◽  
Static Spherically Symmetric Metric ◽  
Theory Of Gravitation ◽  
Spherically Symmetric Metric

The motion of a test body made of electromagnetically interacting point particles, falling in the static spherically symmetric field of the Hermitian theory of gravitation is shown to not disagree with the Eötvös–Dicke–Braginsky experiments for the equivalence principle. The modified Maxwell equations are calculated in the isotropic static spherically symmetric metric, and the role of the equivalence principle in the new theory is discussed in detail.

Complexity factor for dynamical spherically symmetric fluid distributions in f(R) gravity

2019 ◽  
Vol 16 (11) ◽  
pp. 1950170
Author(s):  
H. Nazar ◽  
G. Abbas
Keyword(s):  
Physical Nature ◽  
The Self ◽  
Fluid Distribution ◽  
Spherically Symmetric ◽  
Static Case ◽  
System Configuration ◽  
Prior Investigation ◽  
Text Model ◽  
The Stability ◽  
Stability Results

In this study, we analyze the complexity factor that is extended up to the dynamical spherically symmetric non-static case with anisotropic dissipative self-gravitating fluid distribution in context of [Formula: see text] theory of gravity. For this evaluation we choose the particular [Formula: see text] model that signifies the physical nature of the self-gravitating system. The proposed work discusses not only the complexity factor of the structure of the fluid distribution, but also defines the minimization rate of complexity of the pattern of evolution. Here, first we have applied similar approach for obtaining the structure scalar [Formula: see text] of the complexity factor as used for in the static case, and next we have described explicitly the dissipative and non-dissipative cases by assuming the simplest pattern of evolution (homologous condition). It has been found that the system configuration fulfills the vanishing condition of complexity factor and emerging homologously, corresponds to a energy density homogeneity, shearfree and geodesic, isotropic in pressure. Moreover, we define the stability results for the vanishing complexity factor condition. Finally, we would like to mention that these results are satisfying the prior investigation about complexity factor in General Relativity (GR) by setting [Formula: see text].

scholarly journals Elastic shocks in relativistic rigid rods and balls

2019 ◽  
Vol 475 (2225) ◽  
pp. 20180858 ◽  
Author(s):  
João L. Costa ◽  
José Natário
Keyword(s):  
Free Boundary ◽  
Minkowski Space ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Time Derivative ◽  
Space Time ◽  
Spherically Symmetric ◽  
Soft Phase ◽  
Minkowski Space Time ◽  
Dimensional Minkowski Space

We study the free boundary problem for the ‘hard phase’ material introduced by Christodoulou in (Christodoulou 1995 Arch. Ration. Mech. Anal. 130 , 343–400), both for rods in (1 + 1)-dimensional Minkowski space–time and for spherically symmetric balls in (3 + 1)-dimensional Minkowski space–time. Unlike Christodoulou, we do not consider a ‘soft phase’, and so we regard this material as an elastic medium, capable of both compression and stretching. We prove that shocks must be null hypersurfaces, and derive the conditions to be satisfied at a free boundary. We solve the equations of motion of the rods explicitly, and we prove existence of solutions to the equations of motion of the spherically symmetric balls for an arbitrarily long (but finite) time, given initial conditions sufficiently close to those for the relaxed ball at rest. In both cases we find that the solutions contain shocks if and only if the pressure or its time derivative do not vanish at the free boundary initially. These shocks interact with the free boundary, causing it to lose regularity.

Five-dimensional spherical gravitational collapse of anisotropic fluid with cosmological constant

2017 ◽  
Vol 14 (02) ◽  
pp. 1750025 ◽  
Author(s):  
Suhail Khan ◽  
Hassan Shah ◽  
Ghulam Abbas
Keyword(s):  
Cosmological Constant ◽  
Apparent Horizon ◽  
Physical Significance ◽  
Anisotropic Fluid ◽  
Spherically Symmetric ◽  
Hole Size ◽  
Junction Conditions ◽  
De Sitter ◽  
Positive Cosmological Constant ◽  
Exterior Regions

Our aim is to study five-dimensional spherically symmetric anisotropic collapse with a positive cosmological constant (PCC). For this purpose, five-dimensional spherically symmetric and Schwarzschild–de Sitter metrics are chosen in the interior and exterior regions respectively. A set of junction conditions is derived for the smooth matching of interior and exterior spacetimes. The apparent horizon is calculated and its physical significance is studied. It comes out that the whole collapsing process is influenced by the cosmological constant. The collapsing process under the influence of cosmological constant slows down and black hole size also reduced.

MØLLER ENERGY–MOMENTUM COMPLEX FOR HIGHER-DIMENSIONAL SPHERICALLY SYMMETRIC SPACETIME IN GENERAL RELATIVITY

2012 ◽  
Vol 27 (40) ◽  
pp. 1250231 ◽  
Author(s):  
HÜSNÜ BAYSAL
Keyword(s):  
General Relativity ◽  
Momentum Density ◽  
Momentum Tensor ◽  
Symmetric Model ◽  
Spherically Symmetric ◽  
Higher Dimensional ◽  
Energy And Momentum ◽  
Momentum Complex ◽  
Spherically Symmetric Metric ◽  
Spherically Symmetric Model

We have calculated the total energy–momentum distribution associated with (n+2)-dimensional spherically symmetric model of the universe by using the Møller energy–momentum definition in general relativity (GR). We have found that components of Møller energy and momentum tensor for given spacetimes are different from zero. Also, we are able to get energy and momentum density of various well-known wormholes and black hole models by using the (n+2)-dimensional spherically symmetric metric. Also, our results have been discussed and compared with the results for four-dimensional spacetimes in literature.

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