Junction conditions on null hypersurfaces for spherically symmetric metrics

1991 ◽  
Vol 32 (6) ◽  
pp. 1537-1540
Author(s):  
Zu‐hui Fan ◽  
Zhi‐quan Kuang ◽  
Can‐bin Liang ◽  
Yun‐qiang Yu
Keyword(s):  
Spherically Symmetric ◽  
Junction Conditions ◽  
Null Hypersurfaces ◽  
Symmetric Metrics

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.

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.

Conformal vector fields of static spherically symmetric space-times in f(R, G) gravity

2020 ◽  
Vol 17 (08) ◽  
pp. 2050120
Author(s):  
Fiaz Hussain ◽  
Ghulam Shabbir ◽  
M. Ramzan ◽  
S. F. Hussain ◽  
Sabiha Qazi
Keyword(s):  
Symmetric Space ◽  
Current Literature ◽  
Vector Fields ◽  
Spherically Symmetric ◽  
Direct Integration ◽  
Conformal Vector ◽  
Conformal Vector Fields ◽  
Symmetric Metrics

Assuming the most general form of static spherically symmetric space-times, we search for the conformal vector fields in [Formula: see text] gravity by means of algebraic and direct integration approaches. In this study, there exist six cases which on account of further study yield conformal vector fields of dimension four, six and fifteen. During this study, we also recovered some well-known static spherically symmetric metrics announced in the current literature.

Killing vectors of static spherically symmetric metrics

1990 ◽  
Vol 31 (6) ◽  
pp. 1463-1463 ◽  
Author(s):  
Ashfaque H. Bokhari ◽  
Asghar Qadir
Keyword(s):  
Spherically Symmetric ◽  
Killing Vectors ◽  
Symmetric Metrics

scholarly journals EXPANSIONFREE FLUID EVOLUTION AND SKRIPKIN MODEL IN f(R) THEORY

2011 ◽  
Vol 20 (11) ◽  
pp. 2239-2252 ◽  
Author(s):  
M. SHARIF ◽  
H. RIZWANA KAUSAR
Keyword(s):  
General Relativity ◽  
The Self ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Dynamical Equations ◽  
Constant Energy ◽  
Isotropic Pressure ◽  
Symmetric Star ◽  
Constant Energy Density ◽  
General Influence

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 studied under the general influence of the curvature fluid. Dynamical equations and junction conditions are modified in the context of f(R) dark energy and by taking into account the expansionfree evolution of the self-gravitating fluid. As a particular example, the Skripkin model is investigated which corresponds to isotropic pressure with constant energy density. The results are compared with corresponding results in General Relativity.

Discontinuities in spherically symmetric gravitational fields and shells of radiation

1958 ◽  
Vol 248 (1254) ◽  
pp. 404-414 ◽  
Keyword(s):  
Boundary Conditions ◽  
Spherical Shell ◽  
Previous Treatment ◽  
Empty Space ◽  
Point Of View ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Metric Tensor ◽  
Gravitational Fields

Boundary conditions at a 3-space of discontinuity ∑ are considered from the point of view of Lichnerowicz. The validity of the O’Brien—Synge junction conditions is established for co-ordinates derivable from Lichnerowicz’s ‘admissible co-ordinates’ by a transformation which is uniformly differentiable across ∑. The co-ordinates r , θ , ϕ , t , used by Schwarzschild and most later authors when dealing with spherically symmetric fields, are shown to be of this type. In Schwarzschild’s co-ordinates, the components of the metric tensor can always be made continuous across Ʃ, and simple relations are derived connecting the jumps in their first derivatives. A spherical shell of radiation expanding in empty space is examined in the light of the above ideas, and difficulties encountered by Raychaudhuri in a previous treatment of this problem are cleared up. A particular model is then discussed in some detail.

Harmonic sections of vector bundles with spherically symmetric metrics

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed T. K. Abbassi ◽  
Ibrahim Lakrini
Keyword(s):  
Riemannian Manifold ◽  
Vector Bundle ◽  
Critical Points ◽  
Vector Bundles ◽  
Energy Functional ◽  
Spherically Symmetric ◽  
Arbitrary Vector ◽  
Smooth Maps ◽  
Symmetric Metrics ◽  
Spherically Symmetric Metric

Abstract We equip an arbitrary vector bundle over a Riemannian manifold, endowed with a fiber metric and a compatible connection, with a spherically symmetric metric (cf. [4]), and westudy harmonicity of its sections firstly as smooth maps and then as critical points of the energy functional with variations through smooth sections.We also characterize vertically harmonic sections. Finally, we give some examples of special vector bundles, recovering in some situations some classical harmonicity results.

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