# How far are we from the quantum theory of gravity?

@article{Woodard2009HowFA, title={How far are we from the quantum theory of gravity?}, author={Richard Woodard}, journal={Reports on Progress in Physics}, year={2009}, volume={72}, pages={126002} }

I give a pedagogical explanation of what it is about quantization that makes general relativity go from being a nearly perfect classical theory to a very problematic quantum one. I also explain why some quantization of gravity is unavoidable, why quantum field theories have divergences, why the divergences of quantum general relativity are worse than those of the other forces, what physicists think this means and what they might do with a consistent theory of quantum gravity if they had one…

## 63 Citations

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The different alternatives for observable effects in the propagation of a particle over very large distances that emerge from the new notion of spacetime are discussed, which can be used to favor some alternatives over the others.

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The absence of recognizable, low energy quantum gravitational effects requires that some asymptotic series expansion be wonderfully accurate, but the correct expansion might involve logarithms or…

Gravitational Casimir effect, the Lifshitz theory, and the existence of gravitons

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