scholarly journals The scalar, vector, and tensor modes in gravitational wave turbulence simulations

2021 ◽  
Author(s):  
Axel Brandenburg ◽  
Grigol Gogoberidze ◽  
Tina Kahniashvili ◽  
Sayan Mandal ◽  
Alberto Roper Pol ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Wave Turbulence

scholarly journals Nonlinear diffusion models for gravitational wave turbulence

2019 ◽  
Vol 390 ◽  
pp. 84-88 ◽  
Author(s):  
Sébastien Galtier ◽  
Sergey V. Nazarenko ◽  
Éric Buchlin ◽  
Simon Thalabard
Keyword(s):  
Gravitational Wave ◽  
Nonlinear Diffusion ◽  
Diffusion Models ◽  
Wave Turbulence

scholarly journals A Plausible Model of Inflation Driven by Strong Gravitational Wave Turbulence

Universe ◽  
2020 ◽  
Vol 6 (7) ◽  
pp. 98
Author(s):  
Sébastien Galtier ◽  
Jason Laurie ◽  
Sergey V. Nazarenko
Keyword(s):  
Gravitational Wave ◽  
Particle Physics ◽  
Background Radiation ◽  
Phenomenological Theory ◽  
Accelerated Expansion ◽  
Wave Turbulence ◽  
Field Equations ◽  
Inverse Cascade ◽  
Alternative Hypotheses ◽  
Strong Gravitational Wave

It is widely accepted that the primordial universe experienced a brief period of accelerated expansion called inflation. This scenario provides a plausible solution to the horizon and flatness problems. However, the particle physics mechanism responsible for inflation remains speculative with, in particular, the assumption of a scalar field called inflaton. Furthermore, the comparison with the most recent data raises new questions that encourage the consideration of alternative hypotheses. Here, we propose a completely different scenario based on a mechanism whose origins lie in the nonlinearities of the Einstein field equations. We use the analytical results of weak gravitational wave turbulence to develop a phenomenological theory of strong gravitational wave turbulence where the inverse cascade of wave action plays a key role. In this scenario, the space-time metric excitation triggers an explosive inverse cascade followed by the formation of a condensate in Fourier space whose growth is interpreted as an expansion of the universe. Contrary to the idea that gravitation can only produce a decelerating expansion, our study reveals that strong gravitational wave turbulence could be a source of inflation. The fossil spectrum that emerges from this scenario is shown to be in agreement with the cosmic microwave background radiation measured by the Planck mission. Direct numerical simulations can be used to check our predictions and to investigate the question of non-Gaussianity through the measure of intermittency.

Problems on the Gravitational Wave and the Repulsive Gravitation

2016 ◽  
pp. 4422-4429
Author(s):  
C. Y. Lo
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Einstein Equation ◽  
Wave Solution ◽  
Dynamic Solution ◽  
Pure Mathematics ◽  
Non Linear

It is exciting that the gravitational wave has been confirmed, according to the announcement of LIGO. This would be the time to fix the Einstein equation for the gravitational wave and the nonexistence of the dynamic solution. As a first step, theorists should improve their pure mathematics on non-linear mathematics and related physical considerations beyond Einstein. Then, it is time to rectify the Einstein equation that has no gravitational wave solution which Einstein has recognized, and no dynamic solution that Einstein failed to see. A problem is that physicists in LIGO did not know their shortcomings. Also, in view of the far distance of the sources, it is very questionable that the physicists can determine they are from black holes. Moreover, since the repulsive gravitation can also generate a gravitational wave, the problem of gravitational wave is actually far more complicated than we have known. A useful feature of the gravitational wave based on repulsive gravitation is that it can be easily generated on earth. Thus this can be a new tool for communication because it can penetrate any medium.

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