what are graviton?

Asked by Thoms | 22nd Sep, 2013, 11:28: AM

Expert Answer:

In physics, the graviton is a hypothetical elementary particle that mediates the force of gravitation in the framework of quantum field theory. If it exists, the graviton must be massless (because the gravitational force has unlimited range) and must have a spin of 2. This is because the source of gravitation is the stress-energy tensor, a second-rank tensor, compared toelectromagnetism, the source of which is the four-current, a first-rank tensor. Additionally, it can be shown that any massless spin-2 field would be indistinguishable from gravitation, because a massless spin-2 field must couple to (interact with) the stress-energy tensor in the same way that the gravitational field does.  This result suggests that if a massless spin-2 particle is discovered, it must be the graviton, so that the only experimental verification needed for the graviton may simply be the discovery of a massless spin-2 particle

Answered by  | 22nd Sep, 2013, 12:21: PM

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