Slowly rotating fluid spheres in general relativity

1983 ◽  
Vol 27 (12) ◽  
pp. 3030-3031 ◽  
Author(s):  
Selçuk Ş. Bayin
Keyword(s):  
General Relativity ◽  
Rotating 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.

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

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

Rotating fluid masses in general relativity. II

1966 ◽  
Vol 62 (3) ◽  
pp. 495-501 ◽  
Author(s):  
R. H. Boyer
Keyword(s):  
General Relativity ◽  
Variational Principle ◽  
First Integrals ◽  
Constant Angular Velocity ◽  
Hydrodynamic Equations ◽  
Rotating Fluid ◽  
Axially Symmetric ◽  
Field Equations ◽  
Full Field ◽  
Specific Entropy

AbstractWe describe some properties of a stationary, isolated, axially symmetric, rotating body of perfect fluid, according to general relativity. We first specialize to the case of constant specific entropy and constant angular velocity. The latter condition is equivalent to rigidity in the Born sense; both conditions are consequences of a simple variational principle. The hydrodynamic equations can then be integrated completely. Analogous first integrals are given also for the case of differential rotation. No use is made of the full field equations.

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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