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What is graviphoton?
In theoretical physics, a graviphoton (aka gravivector) is a hypothetical particle which emerges as an excitation of the metric tensor (i.e. gravitational field) in spacetime dimensions higher than four, as described in Kaluza-Klein theory. However, its crucial physical properties are analogous to a (massive)photon: it induces a "vector force", sometimes dubbed a "fifth force". Theelectromagnetic potential emerges from an extra component of the metric tensor , where the figure 5 labels an additional, fifth dimension. In gravity theories with extended supersymmetry (extended supergravities), a graviphoton is normally a superpartner of the graviton that behaves like a photon, and is prone to couple with gravitational strength, as was appreciated in the late 1970s.[2] Unlike the graviton, however, it may provide a repulsive(as well as an attractive) force, and thus, in some technical sense, a type ofanti-gravity. Under special circumstances, then, in several natural models, often descending from five-dimensional theories mentioned, it may actually cancel the gravitational attraction in the static limit.
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