Graviphoton
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In theoretical physics, a graviphoton is a hypothetical particle that emerges as an excitation of the metric tensor (i.e. gravitational field) but whose physical properties are virtually indistinguishable from a photon, as shown in Kaluza-Klein theory. The electromagnetic potential Aμ comes from a component of the metric tensor gμ5 where the figure 5 labels an additional, fifth dimension.
In theories with extended supersymmetry, a graviphoton is usually a superpartner of the graviton that behaves as a photon.