Integrable covariant energy-momentum conservation law for the gravitational field with absolute parallelism structure

1979 ◽  
Vol 39 (1) ◽  
pp. 331-335 ◽  
Author(s):  
G. S. Asanov
2017 ◽  
Vol 384 ◽  
pp. 85-104 ◽  
Author(s):  
Andrew E. Chubykalo ◽  
Augusto Espinoza ◽  
B.P. Kosyakov

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
H. Moradpour ◽  
J. P. Morais Graça ◽  
I. P. Lobo ◽  
I. G. Salako

Accepting the Komar mass definition of a source with energy-momentum tensor Tμν and using the thermodynamic pressure definition, we find a relaxed energy-momentum conservation law. Thereinafter, we study some cosmological consequences of the obtained energy-momentum conservation law. It has been found out that the dark sectors of cosmos are unifiable into one cosmic fluid in our setup. While this cosmic fluid impels the universe to enter an accelerated expansion phase, it may even show a baryonic behavior by itself during the cosmos evolution. Indeed, in this manner, while Tμν behaves baryonically, a part of it, namely, Tμν(e) which is satisfying the ordinary energy-momentum conservation law, is responsible for the current accelerated expansion.


2019 ◽  
Vol 34 (03) ◽  
pp. 1950024 ◽  
Author(s):  
Marcin Daszkiewicz

In this paper, we discuss the energy–momentum conservation principle for two-particle system in the case of canonically and Lie-algebraically twist-deformed Galilei Hopf algebra. Particularly, we provide consistency with the coproducts energy and momentum addition law as well as its symmetric with respect to the exchange of particles counterpart. Besides, we show that the vanishing of total four momentum for two Lie-algebraically deformed kinematical models leads to the discrete values of energies and momenta only in the case of the symmetrized addition rules.


1988 ◽  
Vol 20 (5) ◽  
pp. 485-496 ◽  
Author(s):  
Yi-Shi Duan ◽  
Ji-Cheng Liu ◽  
Xue-Geng Dong

2019 ◽  
Vol 34 (13) ◽  
pp. 1950096 ◽  
Author(s):  
H. Moradpour ◽  
I. Licata ◽  
C. Corda ◽  
Ines G. Salako

Recently, a 4-index generalization of the Einstein theory has been proposed by Moulin [F. Moulin, Eur. Phys. J. C 77, 878 (2017)]. Using this method, we find the most general 2-index field equations derivable from the Einstein–Hilbert action. The application of Newtonian limit, the role of gravitational coupling constant and the effects of the properties of ordinary energy–momentum tensor in obtaining a 4-index gravity theory have been studied. We also address the results of building Weyl free 4-index gravity theory. Our study displays that both the Einstein and Rastall theories can be obtained as the subclasses of a 4-index gravity theory which shows the power of 4-index method in unifying various gravitational theories. It is also obtained that the violation of the energy–momentum conservation law may be allowed in 4-index gravity theory, and moreover, the contraction of 4-index theory generally admits a non-minimal coupling between geometry and matter field in the Rastall way. This study also shows that, unlike the Einstein case, the gravitational coupling constant of 4-index Rastall theory generally differs from that of the ordinary 2-index Rastall theory.


2001 ◽  
Vol 19 (4) ◽  
pp. 605-608
Author(s):  
A.M. IGNATOV ◽  
V.P. POPONIN

The energy-momentum conservation law is used to investigate the interaction of pulses in the framework of nonlinear electrodynamics with Lorentz-invariant constitutive relations. It is shown that for the pulses of the arbitrary shape, the interaction results in phase shift only.


2018 ◽  
Author(s):  
Naftali Tsitverblit

Forced to be flat when nonsingularly described by the equationsof general relativity in a synchronous frame, a region outsidematter sources is recognized to fail in defining space-time curvature consistently with the material nature of the \mbox{Lorentz} transformation.The curvature then extends to such a region only when there is a continuousbackground medium there. Arising from vacuum decay in the universe, as any matter, this medium is thus capable of avoiding the singularity of gravitational collapseas well. The theory of general relativity is then suggested to stem from sucha formulation of the generalized postulate of relativity as also includes thecovariance of energy-momentum conservation for a macroscopically continuousmaterial system, namely the universe. Implying identity between gravitation andinertia, this formulation does not need the principle of equivalence as aseparate postulate. The \mbox{Einstein} tensor is thus interpretable asstanding for the energy-momentum of the gravitational field. In termsof the background medium, its small-amplitude approximation underlainby matter dynamics and phase transitions also describes what isviewable as gravitational waves. In the framework of such amacroscopic interpretation, gravitation ought to beirrelevant to purely microscopic interactions.


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