New solutions for charged anisotropic fluid spheres in general relativity

1995 ◽  
Vol 110 (4) ◽  
pp. 387-393 ◽  
Author(s):  
T. Singh ◽  
G. P. Singh ◽  
A. M. Helmi
Keyword(s):  
General Relativity ◽  
Anisotropic Fluid ◽  
Fluid Spheres

Anisotropic fluid spheres in general relativity

1982 ◽  
Vol 26 (6) ◽  
pp. 1262-1274 ◽  
Author(s):  
Selçuk Ş. Bayin
Keyword(s):  
General Relativity ◽  
Anisotropic Fluid ◽  
Fluid Spheres

Static anisotropic fluid spheres in general relativity with nonuniform density

1992 ◽  
Vol 31 (3) ◽  
pp. 545-551 ◽  
Author(s):  
T. Singh ◽  
G. P. Singh ◽  
R. S. Srivastava
Keyword(s):  
General Relativity ◽  
Anisotropic Fluid ◽  
Fluid Spheres

scholarly journals Counterexamples to the Maximum Force Conjecture

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 403
Author(s):  
Aden Jowsey ◽  
Matt Visser
Keyword(s):  
General Relativity ◽  
Dimensional Analysis ◽  
Maximum Force ◽  
Explicit Calculation ◽  
General Notion ◽  
Physical Situation ◽  
Speed Of Light ◽  
Maximum Tension ◽  
Dimensionless Function ◽  
Fluid Spheres

Dimensional analysis shows that the speed of light and Newton’s constant of gravitation can be combined to define a quantity F*=c4/GN with the dimensions of force (equivalently, tension). Then in any physical situation we must have Fphysical=fF*, where the quantity f is some dimensionless function of dimensionless parameters. In many physical situations explicit calculation yields f=O(1), and quite often f≤1/4. This has led multiple authors to suggest a (weak or strong) maximum force/maximum tension conjecture. Working within the framework of standard general relativity, we will instead focus on idealized counter-examples to this conjecture, paying particular attention to the extent to which the counter-examples are physically reasonable. The various idealized counter-examples we shall explore strongly suggest that one should not put too much credence into any truly universal maximum force/maximum tension conjecture. Specifically, idealized fluid spheres on the verge of gravitational collapse will generically violate the weak (and strong) maximum force conjectures. If one wishes to retain any truly general notion of “maximum force” then one will have to very carefully specify precisely which forces are to be allowed within the domain of discourse.

Evolution of the Universe with two rotating fluids

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040042
Author(s):  
V. F. Panov ◽  
O. V. Sandakova ◽  
E. V. Kuvshinova ◽  
D. M. Yanishevsky
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Scalar Field ◽  
Bianchi Type ◽  
Relativity Theory ◽  
Anisotropic Fluid ◽  
Rotating Fluids ◽  
General Relativity Theory ◽  
Exponential Expansion ◽  
The Universe

An anisotropic cosmological model with expansion and rotation and the Bianchi type IX metric has been constructed within the framework of general relativity theory. The first inflation stage of the Universe filled with a scalar field and an anisotropic fluid is considered. The model describes the Friedman stage of cosmological evolution with subsequent transition to accelerated exponential expansion observed in the present epoch. The model has two rotating fluids: the anisotropic fluid and dust-like fluid. In the approach realized in the model, the anisotropic fluid describes the rotating dark energy.

Some static relativistic compact charged fluid spheres in general relativity

2013 ◽  
Vol 350 (1) ◽  
pp. 293-305 ◽  
Author(s):  
Mohammad Hassan Murad ◽  
Saba Fatema
Keyword(s):  
General Relativity ◽  
Charged Fluid ◽  
Fluid Spheres

General relativistic fluid spheres with variable polytropic index

1966 ◽  
Vol 6 (2) ◽  
pp. 139-147
Author(s):  
R. van der Borght
Keyword(s):  
General Relativity ◽  
Compressible Fluid ◽  
Fluid Sphere ◽  
Polytropic Index ◽  
Field Equations ◽  
Relativistic Fluid ◽  
General Relativistic ◽  
Temperature And Pressure ◽  
Fluid Spheres

AbstractIn this paper we derive solutions of the field equations of general relativity for a compressible fluid sphere which obeys density-temperature and pressure-temperature relations which allow for a variation of the polytropic index throughout the sphere.

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