Graviphoton

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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". The electromagnetic potential A_\mu emerges from an extra component of the metric tensor g_{\mu 5}, where the figure 5 labels an additional, fifth dimension.[1]

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 of anti-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.[2] Joël Scherk investigated semirealistic aspects of this phenomenon,[3] thereby opening up an ongoing search[4][5] for physical manifestations of the mechanism.

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References[edit]

  1. ^ Roy Maartens, "Brane-World Gravity", Living Rev. Relativity, 7, (2004), 7. [1],
  2. ^ a b Cosmas Zachos, "Extended Supergravity with a Gauged Central Charge", Caltech Ph.D. Thesis, (1979), [2]; "N=2 Supergravity Theory With A Gauged Central Charge", Phys Lett, B76, (1979), pp. 329-332. doi:10.1016/0370-2693(78)90799-2
  3. ^ Joel Scherk, "Antigravity: A Crazy Idea?", Phys Lett, B88, (1979), pp. 265-267. doi:10.1016/0370-2693(79)90463-5
  4. ^ David Pollard, "Antigravity and classical solutions of five-dimensional Kaluza-Klein theory", Jou Phys, A16, (1983), pp. 565-574, doi:10.1088/0305-4470/16/3/015.
  5. ^ Fabbrichesi, M.; Roland, K. (1992). "Strong anti-gravity". Nuclear Physics B 388 (2): 539. doi:10.1016/0550-3213(92)90626-M.