Intheoretical physics and quantum physics, agraviphoton orgravivector is a hypothetical particle which emerges as an excitation of themetric tensor (i.e. gravitational field) in spacetime dimensions higher than four, as described inKaluza–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${\displaystyle A_{\mu }}$ emerges from an extra component of the metric tensor${\displaystyle g_{\mu 5}}$, where the figure 5 labels an additional,fifth dimension.^[1]

In gravity theories withextended supersymmetry (extended supergravities), a graviphoton is normally asuperpartner of thegraviton that behaves like a photon, and is prone to couple with gravitational strength, as was appreciated in the late 1970s.^[2] Unlike the graviton, it may provide arepulsive (as well as an attractive) force, and thus, in some technical sense, a type ofanti-gravity. Under special circumstances, in several natural models, often descending from five-dimensional theories mentioned, it may actually cancel the gravitational attraction in the static limit.^[2]Joël Scherk investigated semirealistic aspects of this phenomenon,^[3] stimulating searches^[4][5] for physical manifestations of this mechanism.

• Graviscalar (a.k.a. radion)
• Supergravity
• List of hypothetical particles

• Supersymmetry
• Bosons
• Photons
• Hypothetical elementary particles
• Force carriers
• Subatomic particles with spin 1

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