# Is anti-gravity possible in theoretical physics?

Is anti-gravity http://en.wikipedia.org/wiki/Anti-gravity possible in string theory?

I have read some articles about scientists making assumptions about the existence of anti-gravity, but is it possible in string theory?

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 – Qmechanic♦ Aug 18 '12 at 18:35 Some supergravity theories have a graviphoton (spin-1 vector field) which could provide a repulsive gravitational force and therefore lead to antigravity, see here. – Dilaton Dec 6 '12 at 14:38 What is anti-gravity? It seems that it makes no sense in the same way anti-space or anti-time, or anti-spacetime make no sense. – MBN Dec 6 '12 at 14:48

 but should not gravity depend on the curvature ¿ if the curvature is negative then we would have anti-gravity – Jose Javier Garcia Aug 20 '12 at 21:37 Are you asking why dark energy causes a repulsion when the universe is flat? If so, I'd post this as a new question because it's quite an interesting point and a bit too involved to answer in a comment. – John Rennie Aug 21 '12 at 5:52 In more than two dimensions, 'curvature' is a bit more complicated than just a number. The strong energy condition is equivalent to saying 'gravity is locally attractive' or that the Ricci curvature tensor satisfies $R_{\mu\nu}u^\mu u^\nu \geq 0$ for every future-pointing timelike $u$. – Stan Liou Dec 6 '12 at 16:08