# GR and the role of the graviton

by La Guinee
Tags: graviton, role
 PF Gold P: 4,087 I'm not so sure now but I do know that for gmn to be a covariant tensor, then under transformation from $x^\mu$ to $x^\bar{\mu}$ $$g_{\bar{m}\bar{n}}=g_{mn}A^n_{\bar{n}}A^m_{\bar{m}}$$ where $$A^n_{\bar{n}}=\frac{\partial x^n}{\partial x^\bar{n}}$$ I don't think $\eta_{mn}+h_{mn}$ satisfies this rule. I could be wrong, maybe someone can clarify ?
 P: 308 in my view, quantum gravity (ie, gravitational force as a result of the interaction of graviton particles with other particles) is a non-starter. there is no conceivable mechanism by which particle interaction could result in the perfectly smooth "bending" of light as it passes a massive star.
Emeritus
PF Gold
P: 9,415
 Quote by Mentz114 I'm not so sure now but I do know that for gmn to be a covariant tensor, then under transformation from $x^\mu$ to $x^\bar{\mu}$ $$g_{\bar{m}\bar{n}}=g_{mn}A^n_{\bar{n}}A^m_{\bar{m}}$$ where $$A^n_{\bar{n}}=\frac{\partial x^n}{\partial x^\bar{n}}$$ I don't think $\eta_{mn}+h_{mn}$ satisfies this rule. I could be wrong, maybe someone can clarify ?
I just assumed that the separation of g into two pieces is done like this: You start with a quantity g, which is assumed to be a tensor. Then you just express it as $g=\eta+g-\eta$ where $\eta$ is defined as the tensor that has components $\eta_{\mu\nu}$ in some coordinate system. That makes sure that both $\eta$ and $h$ are tensors.

It's a bit strange that we have to mention a coordinate system. There will be issues to deal with, like "In what coordinate systems are the components of $\eta$ equal to $\eta_{\mu\nu}$?". I don't know anything about how those issues were dealt with. It's been about 10 years since that time when I took a quick look at an old article where they did these things. I never tried to really understand it.
P: 5,632
Fredrik:
 when I try to google for it, this thread comes up in the search results even though It's only been a few hours since I posted the words that matched the search.
You are being watched!!!!

jnorman :
 there is no conceivable mechanism by which particle interaction could result in the perfectly smooth "bending" of light as it passes a massive star.
Harsh assessment..you just killed all of string theory....

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