scholarly journals Astrophysical Tests of Kinematical Conformal Cosmology in Fourth-Order Conformal Weyl Gravity

Galaxies ◽  
2014 ◽  
Vol 2 (4) ◽  
pp. 577-600 ◽  
Author(s):  
Gabriele Varieschi
Keyword(s):  
Fourth Order ◽  
Weyl Gravity ◽  
Conformal Cosmology

scholarly journals Black hole shadows in fourth-order conformal Weyl gravity

2017 ◽  
Vol 95 (12) ◽  
pp. 1299-1306 ◽  
Author(s):  
Jonas R. Mureika ◽  
Gabriele U. Varieschi
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Fourth Order ◽  
Conformal Gravity ◽  
Weyl Gravity ◽  
General Relativistic

We calculate the characteristics of the “black hole shadow” for a rotating, neutral black hole in fourth-order conformal Weyl gravity. It is shown that the morphology is not significantly affected by the underlying framework, except for very large masses. Conformal gravity black hole shadows would also significantly differ from their general relativistic counterparts if the values of the main conformal gravity parameters, γ and κ, were increased by several orders of magnitude. Such increased values for γ and κ are currently ruled out by gravitational phenomenology. Therefore, it is unlikely that these differences in black hole shadows will be detected in future observations, carried out by the Event Horizon Telescope or other such experiments.

scholarly journals Wormhole geometries in fourth-order conformal Weyl gravity

2016 ◽  
Vol 25 (06) ◽  
pp. 1650064 ◽  
Author(s):  
Gabriele U. Varieschi ◽  
Kellie L. Ault
Keyword(s):  
General Relativity ◽  
Fourth Order ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Energy Conditions ◽  
Conformal Gravity ◽  
Flat Spacetime ◽  
Traversable Wormholes ◽  
Weyl Gravity ◽  
The Subject

We present an analysis of the classic wormhole geometries based on conformal Weyl gravity, rather than standard general relativity. The main characteristics of the resulting traversable wormholes remains the same as in the seminal study by Morris and Thorne, namely, that effective super-luminal motion is a viable consequence of the metric. Improving on previous work on the subject, we show that for particular choices of the shape and redshift functions the wormhole metric in the context of conformal gravity does not violate the main energy conditions at or near the wormhole throat. Some exotic matter might still be needed at the junction between our solutions and flat spacetime, but we demonstrate that the averaged null energy condition (as evaluated along radial null geodesics) is satisfied for a particular set of wormhole geometries. Therefore, if fourth-order conformal Weyl gravity is a correct extension of general relativity, traversable wormholes might become a realistic solution for interstellar travel.

Solutions to the Reissner-Nordström, Kerr, and Kerr-Newman problems in fourth-order conformal Weyl gravity

1991 ◽  
Vol 44 (2) ◽  
pp. 417-423 ◽  
Author(s):  
Philip D. Mannheim ◽  
Demosthenes Kazanas
Keyword(s):  
Fourth Order ◽  
Weyl Gravity

Quantum interference effects in conformal Weyl gravity

2017 ◽  
Vol 32 (19n20) ◽  
pp. 1750116 ◽  
Author(s):  
Abdullo Hakimov ◽  
Ahmadjon Abdujabbarov ◽  
Bakhtiyor Narzilloev
Keyword(s):  
Phase Shift ◽  
Fourth Order ◽  
Quantum Interference ◽  
Order Theory ◽  
Interference Effects ◽  
Nonrelativistic Approximation ◽  
Weyl Space ◽  
Weyl Gravity ◽  
The Earth ◽  
Neutron Interferometer

We investigate the effects of conformal gravity as a phase shift by quantum interference and alternate approach of Sagnac effect which is based on the anisotropy of the coordinate speed of light in the fourth-order theory of conformal Weyl space–time. In the nonrelativistic approximation, it has been shown that the phase shift of the interfering particle in neutron interferometer includes the potential terms with the Weyl parameter of the conformal fourth-order theory. Comparing the results of the measurement of the gravitational redshift by the interferometer in the gravitational field of the earth with our theoretical prediction, it has been obtained upper limit for the Weyl parameter as [Formula: see text].

Fourth order Weyl gravity

2006 ◽  
Vol 74 (2) ◽  
Author(s):  
Éanna É. Flanagan
Keyword(s):  
Fourth Order ◽  
Weyl Gravity

Children’s Recall of Approximations to English

1973 ◽  
Vol 16 (2) ◽  
pp. 201-212 ◽  
Author(s):  
Elizabeth Carrow ◽  
Michael Mauldin
Keyword(s):  
Language Development ◽  
Fourth Order ◽  
Third Order ◽  
Memory Processes ◽  
The Third ◽  
General Index ◽  
General Linguistic

As a general index of language development, the recall of first through fourth order approximations to English was examined in four, five, six, and seven year olds and adults. Data suggested that recall improved with age, and increases in approximation to English were accompanied by increases in recall for six and seven year olds and adults. Recall improved for four and five year olds through the third order but declined at the fourth. The latter finding was attributed to deficits in semantic structures and memory processes in four and five year olds. The former finding was interpreted as an index of the development of general linguistic processes.

Exploring the Fourth Order

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Barend KLITSIE ◽  
Rebecca PRICE ◽  
Christine DE LILLE
Keyword(s):  
Action Research ◽  
Fourth Order ◽  
Subject Matter ◽  
Action Research Project ◽  
Research Project ◽  
Building Trust ◽  
Current Business

Companies are organised to fulfil two distinctive functions: efficient and resilient exploitation of current business and parallel exploration of new possibilities. For the latter, companies require strong organisational infrastructure such as team compositions and functional structures to ensure exploration remains effective. This paper explores the potential for designing organisational infrastructure to be part of fourth order subject matter. In particular, it explores how organisational infrastructure could be designed in the context of an exploratory unit, operating in a large heritage airline. This paper leverages insights from a long-term action research project and finds that building trust and shared frames are crucial to designing infrastructure that affords the greater explorative agenda of an organisation.

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