scholarly journals Singularities of plane gravitational waves in Einstein’s general relativity

2020 ◽  
Vol 52 (2) ◽  
Author(s):  
Tongzheng Wang ◽  
Jared Fier ◽  
Bowen Li ◽  
Guoliang Lü ◽  
Zhaojun Wang ◽  
...  
Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1318 ◽  
Author(s):  
Rui Xu

General Relativity predicts two modes for plane gravitational waves. When a tiny violation of Lorentz invariance occurs, the two gravitational wave modes are modified. We use perturbation theory to study the detailed form of the modifications to the two gravitational wave modes from the minimal Lorentz-violation coupling. The perturbation solution for the metric fluctuation up to the first order in Lorentz violation is discussed. Then, we investigate the motions of test particles under the influence of the plane gravitational waves with Lorentz violation. First-order deviations from the usual motions are found.


Nature ◽  
1957 ◽  
Vol 179 (4569) ◽  
pp. 1072-1073 ◽  
Author(s):  
H. BONDI

Colliding plane gravitational waves that lead to the development of a horizon and a subsequent time-like singularity are coupled with an electromagnetic field, a perfect fluid (whose energy density, ∊ , equals the pressure, p ), and null dust (consisting of massless particles). The coupling of the gravitational waves with an electromagnetic field does not affect, in any essential way, the development of the horizon or the time-like singularity if the polarizations of the colliding gravitational waves are not parallel. If the polarizations are parallel, the space-like singularity which occurs in the vacuum is transformed into a horizon followed by a three-dimensional time-like singularity by the merest presence of the electromagnetic field. The coupling of the gravitational waves with an ( ∊ = p )-fluid and null dust affect the development of horizons and singularities in radically different ways: the ( ∊ = p )-fluid affects the development decisively in all cases but qualitatively in the same way, while null dust prevents the development of horizons and allows only the development of space-like singularities. The contrasting behaviours of an ( ∊ = p )-fluid and of null dust in the framework of general relativity is compared with the behaviours one may expect, under similar circumstances, in the framework of special relativity.


Universe ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 43 ◽  
Author(s):  
Jahed Abedi ◽  
Niayesh Afshordi ◽  
Naritaka Oshita ◽  
Qingwen Wang

Black Holes are possibly the most enigmatic objects in our universe. From their detection in gravitational waves upon their mergers, to their snapshot eating at the centres of galaxies, black hole astrophysics has undergone an observational renaissance in the past four years. Nevertheless, they remain active playgrounds for strong gravity and quantum effects, where novel aspects of the elusive theory of quantum gravity may be hard at work. In this review article, we provide an overview of the strong motivations for why “Quantum Black Holes” may be radically different from their classical counterparts in Einstein’s General Relativity. We then discuss the observational signatures of quantum black holes, focusing on gravitational wave echoes as smoking guns for quantum horizons (or exotic compact objects), which have led to significant recent excitement and activity. We review the theoretical underpinning of gravitational wave echoes and critically examine the seemingly contradictory observational claims regarding their (non-)existence. Finally, we discuss the future theoretical and observational landscape for unraveling the “Quantum Black Holes in the Sky”.


2017 ◽  
Vol 9 (3) ◽  
pp. 21
Author(s):  
David Zareski

In previous publications, we showed that Maxwell’s equations are an approximation to those of General Relativity when V<<c, where V is the velocity of the particle submitted to the electromagnetic field. This was demonstrated by showing that the Lienard-Wiechert potential four-vector A_u created by an electric charge is the equivalent of the gravitational four-vector G_u created by a massive neutral point when V<<c. In the present paper, we generalize these results for V non-restricted to be small. To this purpose, we show first that the exact Lagrange-Einstein function of an electric charge q submitted to the field due an immobile charge q_0 is of the same form as that of a particle of mass m submitted to the field created by an immobile particle of mass m_0. Maxwell’s electrostatics is then generalized as a case of the Einstein’s general relativity. In particular, it appears that an immobile q_0 creates also an electromagnetic horizon that behaves like a Schwarzschild horizon. Then, there exist ether gravitational waves constituted by gravitons in the same way as the electromagnetic waves are constituted by photons. Now, since A_u and G_u, are equivalent, and as we show, G_u produces the approximation, for V<<c, of g_u4 created by m_0 mobile, where the g_uv  are the components of Einstein’s fundamental tensor, it follows that A_u+u_u produces the approximation, for V<<c, of Bet_u4 , where the Bet_uv created by m_0 and by q_0, generalize the g_uv.


2009 ◽  
Vol 18 (14) ◽  
pp. 2275-2282 ◽  
Author(s):  
CHRISTIAN CORDA

Even though Einstein's general relativity has achieved great success and passed a lot of experimental tests, it has also shown some shortcomings and flaws which today prompt theorists to ask if it is the definitive theory of gravity. In this essay we show that if advanced projects on the detection of gravitational waves (GWs) improve their sensitivity, allowing us to perform a GW astronomy then accurate angle- and frequency-dependent response functions of interferometers for GWs arising from various theories of gravity, i.e. general relativity and extended theories of gravity, will be the definitive test for general relativity. The papers mentioned in this essay were the world's most-cited in 2007 of the Astroparticle Publication Review of ASPERA with 13 citations.


2021 ◽  
Vol 2081 (1) ◽  
pp. 012014
Author(s):  
O V Babourova ◽  
B N Frolov ◽  
M S Khetzeva ◽  
D V Kushnir

Abstract Plane gravitational waves in the Riemann space of General Relativity is considered. The criterion of plane gravitational waves is used based on the analogy between plane gravitational and electromagnetic waves. The Theorem is proved that the action of the Lie derivative on the plane wave curvature 2-form in the direction of the vector generating the invariance group of this wave in the Riemann space is equal to zero. It is justified that the gravitational waves can be used to transmit information in the Riemann space.


2009 ◽  
Author(s):  
Christian Corda ◽  
Theodore E. Simos ◽  
George Psihoyios ◽  
Ch. Tsitouras

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