Gravitons

January 25th, 2006

Many do not believe the graviton exists, at least in the simplistic manner in which it is envisioned. Superficially speaking, quantum gravity using the gauge interaction of a spin-2 field (graviton) fails to work like the photon and other gauge bosons do.

But more importantly the spin-2, linear wave (classical gravitational wave) is only a perturbation on certain, highly restrictive metrics. In general there are wave-like fluctuations, but they are non-linear, as is often the case in General Relativity. Maxwell’s equations always admit a spin-1, linear wave, but Einstein’s equations rarely admit a spin-2, linear wave, and when they do it is only perturbative and not exact.