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 General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...

in weak-field conditions, but in which

event horizon In astrophysics, an event horizon is a boundary beyond which events cannot affect an observer. Wolfgang Rindler coined the term in the 1950s. In 1784, John Michell proposed that gravity can be strong enough in the vicinity of massive compact obj ...

s cannot appear. Yilmaz's work has been criticized on the grounds that: * his proposed

field equation In theoretical physics and applied mathematics, a field equation is a partial differential equation which determines the dynamics of a physical field, specifically the time evolution and spatial distribution of the field. The solutions to the equat ...

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 A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

* the theory is consistent only with either a completely empty universe or a negative energy vacuum 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 Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics; it deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the vi ...

which goes over to general relativity in an appropriate limit. However Yilmaz has claimed that his theory is "compatible with

quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...

". He suggests that it might be an alternative to

superstring theory Superstring theory is an attempt to explain all of the particles and fundamental forces of nature in one theory by modeling them as vibrations of tiny supersymmetric strings. 'Superstring theory' is a shorthand for supersymmetric string theor ...

. In his theory, Yilmaz wishes to retain the left hand side of the

Einstein field equation In the general theory of relativity, the Einstein field equations (EFE; also known as Einstein's equations) relate the geometry of spacetime to the distribution of matter within it. The equations were published by Einstein in 1915 in the form ...

(namely the

Einstein tensor In differential geometry, the Einstein tensor (named after Albert Einstein; also known as the trace-reversed Ricci tensor) is used to express the curvature of a pseudo-Riemannian manifold. In general relativity, it occurs in the Einstein field eq ...

, which is well-defined for any

Lorentzian manifold In differential geometry, a pseudo-Riemannian manifold, also called a semi-Riemannian manifold, is a differentiable manifold with a metric tensor that is everywhere nondegenerate. This is a generalization of a Riemannian manifold in which the r ...

, independent of general relativity) but to modify the right hand side, the

stress–energy tensor The stress–energy tensor, sometimes called the stress–energy–momentum tensor or the energy–momentum tensor, is a tensor physical quantity that describes the density and flux of energy and momentum in spacetime, generalizing the stress ...

, 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 :Tests of general relativity.

References

* * In this paper,

Charles Misner Charles W. Misner (; born June 13, 1932) is an American physicist and one of the authors of '' Gravitation''. His specialties include general relativity and cosmology. His work has also provided early foundations for studies of quantum gravity ...

argues that Yilmaz's field equation is ill-defined. * * In this preprint, Edward Fackerell criticizes several claims by Yilmaz concerning gtr * * 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.

External links

*One page in the websi
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. {{DEFAULTSORT:Yilmaz Theory Of Gravitation Theories of gravity