scholarly journals A NON- STATIC COSMOLOGICAL MODEL IN THE VECTOR MODEL FOR GRAVITATIONAL FIELD

2011 ◽  
Vol 14 (1) ◽  
pp. 78-84
Author(s):  
On Van Vo
Keyword(s):  
Gravitational Field ◽  
General Theory ◽  
Cosmological Model ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Vector Model ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
S Model

In this paper, based on the vector model for gravitational field we obtained the modified Friedman equations, which were similar to the classical Friedman equations but were added a term of energy – momentum tensor of gravitational field. Non- static flat cosmological model in this model was similar to General Theory of Relativity (GTR) ‘s model but the expansive rate in the vacuum age was difference with General Theory of Relativity ’s model.

scholarly journals Absence of Singularity in Schwarzschild Metric in the Vector Model for Gravitational Field

2012 ◽  
Vol 18 (3) ◽  
pp. 175-184
Author(s):  
Vo Van On
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
General Theory ◽  
Space Time ◽  
Symmetric Body ◽  
Vector Model ◽  
Spherically Symmetric ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Schwarzschild Metric

In this paper, based on the vector model for gravitational field we deduce an equation to determinate the metric of space-time. This equation is similar to equation of Einstein. The metric of space-time outside a static spherically symmetric body is also determined. It gives a small supplementation to the Schwarzschild metric in General theory of relativity but the singularity does not exist. Especially, this model predicts the existence of a new universal body after a black hole.

The Annotated Manuscript

2017 ◽  
Author(s):  
Hanoch Gutfreund ◽  
Jürgen Renn
Keyword(s):  
Gravitational Field ◽  
General Theory ◽  
Equations Of Motion ◽  
Special Theory ◽  
Material Point ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Field Equations ◽  
Theory Of Gravitation

This section presents annotations of the manuscript of Albert Einstein's canonical 1916 paper on the general theory of relativity. It begins with a discussion of the foundation of the general theory of relativity, taking into account Einstein's fundamental considerations on the postulate of relativity, and more specifically why he went beyond the special theory of relativity. It then considers the spacetime continuum, explaining the role of coordinates in the new theory of gravitation. It also describes tensors of the second and higher ranks, multiplication of tensors, the equation of the geodetic line, the formation of tensors by differentiation, equations of motion of a material point in the gravitational field, the general form of the field equations of gravitation, and the laws of conservation in the general case. Finally, the behavior of rods and clocks in the static gravitational field is examined.

scholarly journals New perturbative method for solving the gravitational N-body problem in the general theory of relativity

2015 ◽  
Vol 24 (06) ◽  
pp. 1550039 ◽  
Author(s):  
Slava G. Turyshev ◽  
Viktor T. Toth
Keyword(s):  
Gravitational Field ◽  
General Theory ◽  
Reference Frame ◽  
Coordinate Transformation ◽  
The Body ◽  
Coordinate Transformations ◽  
Theory Of Relativity ◽  
Body System ◽  
General Theory Of Relativity ◽  
Perturbative Method

We present a new approach to describe the dynamics of an isolated, gravitationally bound astronomical N-body system in the weak field and slow-motion approximation of the general theory of relativity. Celestial bodies are described using an arbitrary energy–momentum tensor and assumed to possess any number of internal multipole moments. The solution of the gravitational field equations in any reference frame is presented as a sum of three terms: (i) The inertial flat spacetime in that frame, (ii) unperturbed solutions for each body in the system that is covariantly transformed to the coordinates of this frame and (iii) the gravitational interaction term. We use the harmonic gauge conditions that allow reconstruction of a significant part of the structure of the post-Galilean coordinate transformation functions relating global coordinates of the inertial reference frame to the local coordinates of the noninertial frame associated with a particular body. The remaining parts of these functions are determined from dynamical conditions, obtained by constructing the relativistic proper reference frame associated with a particular body. In this frame, the effect of external forces acting on the body is balanced by the fictitious frame-reaction force that is needed to keep the body at rest with respect to the frame, conserving its relativistic three-momentum. We find that this is sufficient to determine explicitly all the terms of the coordinate transformation. The same method is then used to develop the inverse transformations. The resulting post-Galilean coordinate transformations have an approximate group structure that extends the Poincaré group of global transformations to the case of accelerating observers in a gravitational field of N-body system. We present and discuss the structure of the metric tensors corresponding to the reference frames involved, the rules for transforming relativistic gravitational potentials, the coordinate transformations between frames and the resulting relativistic equations of motion.

scholarly journals Traversable wormholes in the traceless f(R,T) gravity

2021 ◽  
pp. 2150100
Author(s):  
Parbati Sahoo ◽  
P. H. R. S. Moraes ◽  
Marcelo M. Lapola ◽  
P. K. Sahoo
Keyword(s):  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Energy Conditions ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Shape Functions ◽  
Anisotropic Matter ◽  
Traversable Wormholes ◽  
Theory Of Gravitation ◽  
Geometrical Term

Wormholes are tunnels connecting different regions in spacetime. They were obtained originally as a solution for Einstein’s General Theory of Relativity and according to this theory they need to be filled by an exotic kind of anisotropic matter. In the present sense, by “exotic matter” we mean matter that does not satisfy the energy conditions. In this paper, we propose the modeling of traversable wormholes (i.e. wormholes that can be safely crossed) within an alternative gravity theory that proposes an extra material (rather than geometrical) term in its gravitational action, namely the traceless [Formula: see text] theory of gravitation, with [Formula: see text] and [Formula: see text] being, respectively, the Ricci scalar and trace of the energy–momentum tensor. Our solutions are obtained from well-known particular cases of the wormhole metric potentials, namely redshift and shape functions. In possession of the solutions for the wormhole material content, we also apply the energy conditions to them. The features of those are carefully discussed.

scholarly journals ON THE SPECTRAL SHIFT AND THE TIME DELAY OF LIGHT IN A RINDLER ACCELERATED FRAME

2007 ◽  
Vol 16 (04) ◽  
pp. 699-709 ◽  
Author(s):  
J. B. FORMIGA ◽  
C. ROMERO
Keyword(s):  
Gravitational Field ◽  
Time Delay ◽  
General Theory ◽  
Equivalence Principle ◽  
Spectral Shift ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Accelerated Observers ◽  
Einstein's Equivalence Principle

We discuss two effects predicted by the general theory of relativity in the context of Rindler accelerated observers: the gravitational spectral shift and the time delay of light. We show that these effects also appear in a Rindler frame in the absence of gravitational field, in accordance with the Einstein's equivalence principle.

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