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 vμ—an external quantity, which we fix to be a nonvanishing 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 or enhanced by the extension.
- Publication:
-
Physical Review D
- Pub Date:
- November 2003
- DOI:
- 10.1103/PhysRevD.68.104012
- arXiv:
- arXiv:gr-qc/0308071
- Bibcode:
- 2003PhRvD..68j4012J
- Keywords:
-
- 04.20.Cv;
- 04.50.+h;
- Fundamental problems and general formalism;
- Gravity in more than four dimensions Kaluza-Klein theory unified field theories;
- alternative theories of gravity;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Theory
- E-Print:
- 19 pages, added references, an addition in section 5