scholarly journals Darmois matching and C3 matching

2021 ◽  
Author(s):  
Antonio C. Gutierrez-Pineres ◽  
Hernando Quevedo
Keyword(s):  
Perfect Fluid ◽  
Vacuum Solution ◽  
Spherically Symmetric ◽  
Matching Conditions ◽  
Physical Behavior ◽  
Symmetric Spacetimes ◽  
Spherically Symmetric Spacetimes

Abstract We apply the Darmois and the $C^3$ matching conditions to three different spherically symmetric spacetimes. The exterior spacetime is described by the Schwarzschild vacuum solution whereas for the interior counterpart we choose different perfect fluid solutions with the same symmetry. We show that Darmois matching conditions are satisfied in all the three cases whereas the $C^3$ conditions are not fulfilled. We argue that this difference is due to a non-physical behavior of the pressure on the matching surface.

scholarly journals SOME PROPERTIES OF THE "STRING GAS" WITH THE EQUATION OF STATE $p = -\frac{1}{3} \rho$

2012 ◽  
Vol 21 (01) ◽  
pp. 1250004 ◽  
Author(s):  
ALEXANDER YU. KAMENSHCHIK ◽  
ISAAK M. KHALATNIKOV
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Perfect Fluid ◽  
Spherically Symmetric ◽  
Rotation Curves ◽  
Matter Effects ◽  
Symmetric Spacetimes ◽  
State Formula ◽  
Spherically Symmetric Spacetimes

We show that the string gas — a perfect fluid with the equation of state [Formula: see text] possesses rather interesting properties. In Friedmann universes its presence can change the observable topology of the space; in the spherically symmetric spacetimes it produces rather bizzare geometries and in a way its influence on the rotation curves mimics the dark matter effects.

Homothetic Ricci collineations of non-static spherically symmetric spacetimes with perfect fluid matter

2018 ◽  
Vol 33 (34) ◽  
pp. 1850196
Author(s):  
Tahir Hussain ◽  
Sumaira Saleem Akhtar ◽  
Fawad Khan
Keyword(s):  
Perfect Fluid ◽  
Infinite Number ◽  
Ricci Tensor ◽  
Spherically Symmetric ◽  
Ricci Collineations ◽  
Symmetric Spacetimes ◽  
Fluid Matter ◽  
Spherically Symmetric Spacetimes ◽  
Static Spherically Symmetric Spacetimes

Non-static spherically symmetric spacetimes with perfect fluid matter are considered and their homothetic Ricci collineations (HRCs) are investigated for degenerate as well as non-degenerate Ricci tensor. The present analysis shows that, for non-degenerate Ricci tensor, the possible number of HRCs admitted by these spacetimes is 5, 6 or 7, while they possess 4, 11 or otherwise infinite number of HRCs when the Ricci tensor is degenerate.

Classification of Static Spherically Symmetric Spacetimes by Noether Symmetries

2013 ◽  
Vol 52 (10) ◽  
pp. 3534-3542 ◽  
Author(s):  
Ashfaque H. Bokhari ◽  
A. G. Johnpillai ◽  
A. H. Kara ◽  
F. M. Mahomed ◽  
F. D. Zaman
Keyword(s):  
Spherically Symmetric ◽  
Noether Symmetries ◽  
Symmetric Spacetimes ◽  
Spherically Symmetric Spacetimes ◽  
Static Spherically Symmetric Spacetimes

scholarly journals REISSNER–NORDSTRÖM SOLUTIONS AND ENERGY IN TELEPARALLEL THEORY

2006 ◽  
Vol 21 (29) ◽  
pp. 2241-2250 ◽  
Author(s):  
GAMAL G. L. NASHED
Keyword(s):  
Spherically Symmetric ◽  
Tetrad Field ◽  
Symmetric Spacetimes ◽  
Time Space ◽  
Teleparallel Theory ◽  
Theory Of Gravitation ◽  
Spherically Symmetric Spacetimes ◽  
Charged Source ◽  
Superpotential Method ◽  
Tetrad Theory

We give three different spherically symmetric spacetimes for the coupled gravitational and electromagnetic fields with charged source in the tetrad theory of gravitation. One of these contains an arbitrary function and generates the others. These spacetimes give the Reissner–Nordström metric black hole. We then calculated the energy associated with these spacetimes using the superpotential method. We find that unless the time-space components of the tetrad field go to zero faster than [Formula: see text] at infinity, one gets different results for the energy.

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