Yilmaz theory of gravitation

The Yilmaz theory of gravitation is an attempt by Huseyin Yilmaz (1924-2013) (Turkish: Hüseyin Yılmaz) and his coworkers to formulate a classical field theory of gravitation which is similar to general relativity in weak-field conditions, but in which event horizons cannot appear.

Yilmaz's work has been criticized on the grounds that

his proposed field equation is ill-defined,
event horizons can occur in weak field situations according to the general theory of relativity, in the case of a supermassive black hole.
the theory is consistent only with either a completely empty universe or a negative energy vacuum^[1]

It is well known that attempts to quantize general relativity along the same lines which lead from Maxwell's classical field theory of electromagnetism to quantum electrodynamics fail, and that it has proven very difficult to construct a theory of quantum gravity which goes over to general relativity in an appropriate limit. However Yilmaz has claimed that his theory is 'compatible with quantum mechanics'. He suggests that it might be an alternative to superstring theory.

In his theory, Yilmaz wishes to retain the left hand side of the Einstein field equation (namely the Einstein tensor, which is well-defined for any Lorentzian manifold, independent of general relativity) but to modify the right hand side, the stress–energy tensor, by adding a kind of gravitational contribution. According to Yilmaz's critics, this additional term is not well-defined, and cannot be made well defined.

No astronomers have tested his ideas, although some have tested competitors of general relativity; see Category:Tests of general relativity.

External links

One page in the website Relativity on the World Wide Web (archived link) lists some apparent misstatements by Yilmaz concerning the general theory of relativity, similar to those discussed by Fackerell.

References

↑ Ibison, M. (2006). "Cosmological test of the Yilmaz theory of gravity". Classical Quantum Gravity. 23 (3): 577–589. arXiv:0705.0080. Bibcode:2006CQGra..23..577I. doi:10.1088/0264-9381/23/3/001.

Yilmaz, H. (1992). "Toward a field theory of gravitation". Nuovo Cimento B. 107 (8): 941–960. Bibcode:1992NCimB.107..941Y. doi:10.1007/BF02899296.
Misner, C. W. (1999). "Yilmaz Cancels Newton". Nuovo Cimento B. 114: 1079–1085. arXiv:gr-qc/9504050. Bibcode:1999NCimB.114.1079M. In this paper, Charles Misner argues that Yilmaz's field equation is ill-defined.
Alley, C.O.; Aschan, P. K.; Yilmaz, H. (1995). "Refutation of C. W. Misner's claims in his article "Yilmaz Cancels Newton"". arXiv:gr-qc/9506082 [gr-qc].
Fackerell, E. D. (2006). "Remarks on the Yilmaz and Alley papers". School of Mathematics and Statistics F07, University of Sydney. In this preprint, Edward Fackerell criticizes several claims by Yilmaz concerning gtr
Alley, C. O.; Yilmaz, H. (2000). "Response to Fackerell's Article". arXiv:gr-qc/0008040 [gr-qc].
Misner, C.; Thorne, K. S.; Wheeler, J. A. (1973). Gravitation. W. H. Freeman. ISBN 0-7167-0344-0. See section 20.4 for nonlocal nature of gravitational field energy, and all of chapter 20 for relation between integration, Bianchi identities, and 'conservation laws' in curved spacetimes.

Theories of gravitation

Standard

Newtonian gravity (NG)	Newton's law of universal gravitation History of gravitational theory

General relativity (GR)	Introduction History Mathematics Resources Tests Post-Newtonian formalism Linearized gravity ADM formalism Gibbons–Hawking–York boundary term

Alternatives to
general relativity

Paradigms	Classical theories of gravitation Quantum gravity Theory of everything

Classical	Einstein–Cartan Bimetric theories Gauge theory gravity Teleparallelism Composite gravity f(R) gravity Massive gravity Modified Newtonian dynamics (MOND) Nonsymmetric gravitation Scalar–tensor theories Brans–Dicke Scalar–tensor–vector Conformal gravity Scalar theories Nordström Whitehead Geometrodynamics Induced gravity Tensor–vector–scalar Chameleon Pressuron

Quantisation	Euclidean quantum gravity Canonical quantum gravity Wheeler–DeWitt equation Loop quantum gravity Spin foam Causal dynamical triangulation Causal sets DGP model

Unification	Kaluza–Klein theory Dilaton Supergravity

Unification and quantisation	Noncommutative geometry Self-creation cosmology Semiclassical gravity Superfluid vacuum theory Logarithmic BEC vacuum String theory M-theory F-theory Heterotic string theory Type I string theory Type 0 string theory Bosonic string theory Type II string theory Little string theory Twistor theory Twistor string theory

Generalisations / Extensions of GR	Scale relativity Liouville gravity Lovelock theory (2+1)-dimensional topological gravity Gauss–Bonnet gravity Jackiw–Teitelboim gravity

Pre-Newtonian theories
and Toy models

This article is issued from Wikipedia - version of the 9/6/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.