# Gravitons & Relativity

1. Jul 12, 2008

### QUANTUMQ

does the idea of how gravity works through gravitons contradict einsteins general relativity?
the idea of a particle exchange (gravitons) does dont seem to agree with space-time fabric.
can they agree or is only one right? if so which do you think?

2. Jul 12, 2008

### humanino

I can tell you that you can find Einstein's equations starting from the hypothesis of a massless spin-2 exchange. But I agree that, apart from being spin-2, we don't know much how the graviton should be defined. The obvious idea is $$g=\eta+h$$ where $$g$$ is the metric, $$\eta$$ is the metric of the vacuum, and $$h$$ is your graviton field. This idea does not allow you to couple fermions to the graviton. Sometimes we take the vierbein, which is "roughly speaking" the square root of the metric, to be related more directly to the graviton field.