Carroll, Sean M. and Tam, Heywood and Wehus, Ingunn Kathrine (2009) Lorentz violation in Goldstone gravity. Physical Review D, 80 (2). 025020. ISSN 0556-2821 http://resolver.caltech.edu/CaltechAUTHORS:20090817-144813345
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We consider a theory of gravity in which a symmetric two-index tensor in Minkowski spacetime acquires a vacuum expectation value (vev) via a potential, thereby breaking Lorentz invariance spontaneously. When the vev breaks all the generators of the Lorentz group, six Goldstone modes emerge, two linear combinations of which have properties that are identical to those of the graviton in general relativity. Integrating out massive modes yields an infinite number of Lorentz-violating radiative-correction terms in the low-energy effective Lagrangian. We examine a representative subset of these terms and show that they modify the dispersion relation of the two propagating graviton modes such that their phase velocity is direction dependent. If the phase velocity of the Goldstone gravitons is subluminal, cosmic rays can emit gravi-Cherenkov radiation, and the detection of high-energy cosmic rays can be used to constrain these radiative-correction terms. Test particles in the vicinity of the Goldstone gravitons undergo longitudinal oscillations in addition to the usual transverse oscillations as predicted by general relativity. Finally, we discuss the possibility of having vevs that do not break all six generators and examine in detail one such theory.
|Additional Information:||©2009 The American Physical Society. Received 23 June 2009; published 28 July 2009. We are grateful to Arthur Lipstein for useful discussions. This work was supported in part by the U.S. Department of Energy and by the Gordon and Betty Moore Foundation. I.K.W acknowledges financial support from the Research Council of Norway. 11.30.Cp Lorentz and Poincaré invariance in particles and fields 12.60.-i Models beyond the standard model 04.50.Kd Modified theories of gravity|
|Subject Keywords:||PACS: 11.30.Cp; 12.60.-i; 04.50.Kd|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||George Porter|
|Deposited On:||08 Sep 2009 20:51|
|Last Modified:||26 Dec 2012 11:12|
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