Graviphoton

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 A_μ comes from a component of the metric tensor g_μ5 where the figure 5 labels an additional, fifth dimension.