scholarly journals Impulsive gravitational waves of massless particles in extended theories of gravity

2012 ◽  
Vol 85 (6) ◽  
Author(s):  
Morteza Mohseni
Keyword(s):  
Gravitational Waves ◽  
Massless Particles ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Extended Theories

scholarly journals INTERFEROMETRIC DETECTION OF GRAVITATIONAL WAVES: THE DEFINITIVE TEST FOR GENERAL RELATIVITY

2009 ◽  
Vol 18 (14) ◽  
pp. 2275-2282 ◽  
Author(s):  
CHRISTIAN CORDA
Keyword(s):  
General Relativity ◽  
Gravitational Waves ◽  
Experimental Tests ◽  
Great Success ◽  
Response Functions ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Interferometric Detection ◽  
Extended Theories ◽  
Einstein’S General Relativity

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.

scholarly journals Gravitational waves in the extended theory of gravity

2021 ◽  
Author(s):  
Sourav Roy Chowdhury ◽  
Maxim Khlopov
Keyword(s):  
General Relativity ◽  
Gravitational Waves ◽  
Degrees Of Freedom ◽  
Standard Theory ◽  
New Approach ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Theory Of Gravity ◽  
New Formula ◽  
Extended Theories

Extended theories of gravity are considered as a new approach for solving the infrared and ultraviolet scale problems; the standard theory of gravity (general relativity) and observational evidence of gravitational waves and subsequent identification of the number of existing polarizations are an effective tool for testing general relativity and extended theories of gravity. The Newman–Penrose method is used to characterize the polarization modes for specific forms of [Formula: see text] in the present study. Both the forms of the [Formula: see text] theory belong to far more general variational class of gravitational waves, capable of presenting up to six separate polarizations states. We have introduced a new [Formula: see text] gravity model as an attempt to have a theory with more parametric regulations so that the model can be used to describe existing issues and discover different directions in gravity physics. The primary goal of this research is to look into the properties of gravitational waves with new cases. The model shows the existence of scalar degrees of freedom in [Formula: see text] gravity metric notation.

Shadow from a rotating black hole in an extended gravity

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040060
Author(s):  
Vjacheslav Prokopov ◽  
Stanislav Alexeyev
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Rotating Black Hole ◽  
Extended Gravity ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Extended Theories

We focus on the consequences of that the Event Horizon Telescope obtained images of the black hole shadow in the center of the M87 galaxy. We show that to test extended theories of gravity the improving of the resolution by 3 orders is necessary. In addition it is demonstrated that the rotation distorts the shape of the shadow and corrections from the extended gravity may affect on this distortion.

scholarly journals Evaporation/Antievaporation and energy conditions in alternative gravity

2018 ◽  
Vol 33 (04) ◽  
pp. 1850030 ◽  
Author(s):  
Andrea Addazi
Keyword(s):  
General Relativity ◽  
Degrees Of Freedom ◽  
Energy Conditions ◽  
Raychaudhuri Equation ◽  
Bonnet Gravity ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Extended Theories ◽  
Alternative Gravity

We discuss the evaporation and antievaporation instabilities of Nariai solution in extended theories of gravity. These phenomena were explicitly shown in several different extensions of General Relativity, suggesting that a universal cause is behind them. We show that evaporation and antievaporation are originated from deformations of energy conditions on the Nariai horizon. Energy conditions get new contributions from the extra propagating degrees of freedom, which can provide extra focalizing or antifocalizing terms in the Raychaudhuri equation. We show the two explicit cases of [Formula: see text]-gravity and Gauss–Bonnet gravity.

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