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arXiv · gr-qc/0308071

Chern-Simons Modification of General Relativity

R. Jackiw·S. -Y. Pi
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Abstract

General relativity is extended by promoting the three-dimensional gravitational Chern-Simons term to four dimensions. This entails choosing an embedding coordinate v_μ-- an external quantity, which we fix to be a non-vanishing constant in its time component. The theory is identical to one in which the embedding coordinate is itself a dynamical variable, rather than a fixed, external quantity. Consequently diffeomorphism symmetry breaking is hidden in the modified theory: the Schwarzschild metric is a solution; gravitational waves possess two polarizations, each traveling at the velocity of light; a conserved energy-momentum (pseudo-) tensor can be constructed. The modification is visible in the intensity of gravitational radiation: the two polarizations of a gravity wave carry intensities that are suppressed/enchanced by the extension.

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R. Jackiw, S. -Y. Pi. 2003-10-07. Chern-Simons Modification of General Relativity. https://doi.org/10.1103/physrevd.68.104012

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