Spherically symmetric gravitational fields of isolated objects

2010 ◽  
pp. 168-221
Author(s):  
Jerzy Plebanski ◽  
Andrzej Krasinski
Keyword(s):  
Spherically Symmetric ◽  
Gravitational Fields

Spherically Symmetric Gravitational Fields

1965 ◽  
Vol 6 (1) ◽  
pp. 1-5 ◽  
Author(s):  
P. G. Bergmann ◽  
M. Cahen ◽  
A. B. Komar
Keyword(s):  
Spherically Symmetric ◽  
Gravitational Fields

scholarly journals PARAMETRIC INSTABILITY IN SCALAR GRAVITATIONAL FIELDS

2012 ◽  
Vol 27 (24) ◽  
pp. 1230023 ◽  
Author(s):  
TREVOR B. DAVIES ◽  
CHARLES H.-T. WANG ◽  
ROBERT BINGHAM ◽  
J. TITO MENDONÇA
Keyword(s):  
Gravitational Field ◽  
Field Effect ◽  
Strong Field ◽  
Parametric Instability ◽  
Spherically Symmetric ◽  
Scalar Tensor Theory ◽  
Subsequent Work ◽  
Dynamical Mechanism ◽  
Gravitational Fields ◽  
Tensor Theory

We present a brief review on a new dynamical mechanism for a strong field effect in scalar–tensor theory. Starting with a summary of the essential features of the theory and subsequent work by several authors, we analytically investigate the parametric excitation of a scalar gravitational field in a spherically symmetric radially pulsating neutron star.

scholarly journals The theory of spherically symmetric thin shells in conformal gravity

2018 ◽  
Vol 27 (06) ◽  
pp. 1841012 ◽  
Author(s):  
Victor Berezin ◽  
Vyacheslav Dokuchaev ◽  
Yury Eroshenko
Keyword(s):  
General Relativity ◽  
Weyl Tensor ◽  
Delta Function ◽  
Einstein Gravity ◽  
Riemann Tensor ◽  
Momentum Tensor ◽  
Thin Shells ◽  
Spherically Symmetric ◽  
Gravitational Fields ◽  
Gravitational Theories

The spherically symmetric thin shells are the nearest generalizations of the point-like particles. Moreover, they serve as the simple sources of the gravitational fields both in General Relativity and much more complex quadratic gravity theories. We are interested in the special and physically important case when all the quadratic in curvature tensor (Riemann tensor) and its contractions (Ricci tensor and scalar curvature) terms are present in the form of the square of Weyl tensor. By definition, the energy–momentum tensor of the thin shell is proportional to Diracs delta-function. We constructed the theory of the spherically symmetric thin shells for three types of gravitational theories with the shell: (1) General Relativity; (2) Pure conformal (Weyl) gravity where the gravitational part of the total Lagrangian is just the square of the Weyl tensor; (3) Weyl–Einstein gravity. The results are compared with these in General Relativity (Israel equations). We considered in detail the shells immersed in the vacuum. Some peculiar properties of such shells are found. In particular, for the traceless ([Formula: see text] massless) shell, it is shown that their dynamics cannot be derived from the matching conditions and, thus, is completely arbitrary. On the contrary, in the case of the Weyl–Einstein gravity, the trajectory of the same type of shell is completely restored even without knowledge of the outside solution.

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.

scholarly journals Gravastars in a non-minimally coupled gravity with electromagnetism

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Özcan Sert ◽  
Muzaffer Adak
Keyword(s):  
Dark Energy ◽  
Exact Solutions ◽  
Free Parameter ◽  
Maxwell Model ◽  
Spherically Symmetric ◽  
Minimal Models ◽  
Coupled Models ◽  
Gravitational Fields ◽  
Gravitational Vacuum ◽  
Physical Quantities

AbstractIn this paper we investigate the gravitational vacuum stars which called gravastars in the non-minimally coupled models with electromagnetic and gravitational fields. We consider two non-minimal models and find the corresponding spherically symmetric exact solutions in the interior of the star consisting of the dark energy condensate. Our models turn out to be Einstein–Maxwell model at the outside of the star and the solutions become the Reissner–Nordström solution. The physical quantities of these models are continuous and non-singular in some range of parameters and the exterior geometry continuously matches with the interior geometry at the surface. We calculate the matter mass, the total gravitational mass, the electric charge and redshift of the star for the two models. We notice that these quantities except redshift are dependent of a subtle free parameter, k, of the model. We also remark a wide redshift range from zero to infinity depending on one free parameter, $$\beta $$ β , in the second model.

scholarly journals On the classic geometrodynamics of a spherically-symmetric configuration of gravitational and electromagnetic fields

2019 ◽  
Vol 27 (1) ◽  
pp. 3-8
Author(s):  
V. D. Gladush
Keyword(s):  
Hamiltonian Constraint ◽  
Spherically Symmetric ◽  
Action Functional ◽  
Hamiltonian Action ◽  
Gravitational Fields ◽  
Motion Trajectories ◽  
Symmetric Configuration ◽  
Functional Derivatives ◽  
Derivatives Of ◽  
Hamilton Jacobi Equation

Analytical aspects of the classical geometrodynamics for the spherically-symmetric configuration of the electromagnetic and gravitational fields in GR are considered. The feature of such configurations is that they admit two motion integrals – the total mass and charge. The Einstein-Hilbert action for the configuration, after dimensional reduction, by means of the Legendre transformation is reduced to the Hamiltonian action. Using the conservation laws for the mass and charge, as well as the Hamiltonian constraint, the momenta are found as functions of configuration variables. The set of equations, which associate momenta and functional derivatives of the action in the configuration space (CS) is integrable. This allows us to obtain the action functional as a solution of the Einstein-Hamilton-Jacobi equation in functional derivatives. Variations of the action functional with respect to mass M and charge Q of the configuration lead to the motion trajectories in the CS. We note that the minisuperspace metric, which is induced by the kinetic part of the Lagrangian, does not coincide with the CS metric that arises when the function of lapse N is excluded from the action. The space-time metric for which the indicated metrics coincide in the T-region up to a coefficient are considered. The metric of CS is constructed and its geometry is studied. Under the trivial embedding of hypersurfaces of the foliation into a dynamical T-region, the CS is flat. It allows introducing pseudo-Cartesian coordinates in which the CS metric takes the Lorentz form.

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