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What is the best way to see that the number of propagating degrees of freedom or gravitons in 3 dimensions is $0$ ? By graviton I mean the metric and NOT some topologically massive graviton that one can include in the Lagrangian. Also is the number in 4-dimensions 2?

Qmechanic
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dbranes
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1 Answers1

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The Weyl tensor vanishes in 3 dimensions, so the only remaining gravitational degrees of freedom are the Ricci coefficients, but they're tied to matter sources by the Einstein equations so aren't "propagating" degrees of freedom.

twistor59
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