In theoretical physics
, the nonsymmetric gravitational theory
(NGT) of is a classical theory of which tries to explain the observation of the flat .
In general relativity
, the gravitational field is characterized by a symmetric
, the metric tensor
. The possibility of generalizing the metric tensor has been considered by many, including Einstein
and others. A general (nonsymmetric) tensor can always be decomposed into a symmetric and an antisymmetric
part. As the electromagnetic field
is characterized by an antisymmetric rank-2 tensor, there is an obvious possibility for a unified theory
: a nonsymmetric tensor composed of a symmetric part representing gravity, and an antisymmetric part that represents electromagnetism. Research in this direction ultimately proved fruitless; the desired classical unified field theory was not found.
In 1979, Moffat made the observation that the field corresponding with the antisymmetric part need not be massless, like the electromagnetic (or gravitational) fields.
In its original form, the theory may be unstable, although this has only been shown in the case of the linearized version.<ref... Read More