Chern-Simons Modification of General Relativity
Abstract
General relativity is extended by promoting the three-dimensional gravitational Chern-Simons term to four dimensions. This entails choosing an embedding coordinate v_\mu -- 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.
Cite
@article{arxiv.gr-qc/0308071,
title = {Chern-Simons Modification of General Relativity},
author = {R. Jackiw and S. -Y. Pi},
journal= {arXiv preprint arXiv:gr-qc/0308071},
year = {2014}
}
Comments
19 pages, added references, an addition in section 5