scholarly journals SPHERICALLY SYMMETRIC THICK BRANES IN VACUUM

2004 ◽  
Vol 19 (27) ◽  
pp. 4687-4694 ◽  
Author(s):  
MASSOUD BORHANI ◽  
REZA MANSOURI ◽  
SAMAD KHAKSHOURNIA
Keyword(s):  
Finite Thickness ◽  
Equation Of Motion ◽  
Space Time ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Bulk Space ◽  
Thick Branes

We consider a spherical thick 3-brane immersed in a five-dimensional bulk space–time. We demonstrate how the thick brane equation of motion expanded in powers of the thickness of the brane can be obtained from the expected junction conditions on the boundaries of thick brane with the two embedding space–times. It is shown that the finite thickness corrections lead to a faster collapse of the brane in the vacuum.

Higher dimensional shear-free radiating collapse

2018 ◽  
Vol 96 (11) ◽  
pp. 1201-1204
Author(s):  
Hassan Shah ◽  
Zahid Ahmad ◽  
Suhail Khan
Keyword(s):  
Heat Flux ◽  
Symmetric Space ◽  
Temperature Profile ◽  
Space Time ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Conformally Flat ◽  
Suggested Model ◽  
Proposed Model ◽  
Higher Dimensional

In this paper, shear-free gravitational collapse with heat flux is discussed by considering higher dimensional spherically symmetric space–time as interior metric and higher dimensional Vaidya space–time as exterior metric. The effects of dissipation on collapse are investigated. A simple approximate higher dimensional conformally flat model is proposed that satisfies the junction conditions. Temperature profile of the proposed model is also calculated. It is concluded that dissipation decreases the collapsing rate and temperature profile of the suggested model.

scholarly journals Janis–Newman–Winicour and Wyman Solutions are the Same

1997 ◽  
Vol 12 (27) ◽  
pp. 4831-4835 ◽  
Author(s):  
K. S. Virbhadra
Keyword(s):  
Exact Solution ◽  
Scalar Field ◽  
Total Energy ◽  
Space Time ◽  
Massless Scalar ◽  
Spherically Symmetric ◽  
Scalar Equations

We show that the well-known most general static and spherically symmetric exact solution to the Einstein-massless scalar equations given by Wyman is the same as one found by Janis, Newman and Winicour several years ago. We obtain the energy associated with this space–time and find that the total energy for the case of the purely scalar field is zero.

scholarly journals TRAVERSABLE WORMHOLES IN A STRING CLOUD

2008 ◽  
Vol 17 (08) ◽  
pp. 1179-1196 ◽  
Author(s):  
MARTÍN G. RICHARTE ◽  
CLAUDIO SIMEONE
Keyword(s):  
Thin Shell ◽  
Dimensional Space ◽  
Space Time ◽  
Exotic Matter ◽  
Spherically Symmetric ◽  
Related Model ◽  
Traversable Wormholes ◽  
Dimensional Space Time ◽  
Thin Shell Wormholes ◽  
The Stability

We study spherically symmetric thin shell wormholes in a string cloud background in (3 + 1)-dimensional space–time. The amount of exotic matter required for the construction, the traversability and the stability of such wormholes under radial perturbations are analyzed as functions of the parameters of the model. In addition, in the appendices a nonperturbative approach to the dynamics and a possible extension of the analysis to a related model are briefly discussed.

scholarly journals Study of charged compact stars with class 1 metric under general relativity

2019 ◽  
Vol 97 (12) ◽  
pp. 1323-1331 ◽  
Author(s):  
S.K. Maurya ◽  
S. Roy Chowdhury ◽  
Saibal Ray ◽  
B. Dayanandan
Keyword(s):  
General Relativity ◽  
Compact Star ◽  
Space Time ◽  
Electron Cloud ◽  
Compact Stars ◽  
Stellar Structure ◽  
Spherically Symmetric ◽  
Class 1 ◽  
Maxwell Space ◽  
Physical Tests

In the present paper we study compact stars under the background of Einstein–Maxwell space–time, where the 4-dimensional spherically symmetric space–time of class 1 along with the Karmarkar condition has been adopted. The investigations, via the set of exact solutions, show several important results, such as (i) the value of density on the surface is finite; (ii) due to the presence of the electric field, the outer surface or the crust region can be considered to be made of electron cloud; (iii) the charge increases rapidly after crossing a certain cutoff region (r/R ≈ 0.3); and (iv) the avalanche of charge has a possible interaction with the particles that are away from the center. As the stellar structure supports all the physical tests performed on it, therefore the overall observation is that the model provides a physically viable and stable compact star.

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