Lorentz Violation in Goldstone Gravity
Sean M. Carroll, Heywood Tam, Ingunn Kathrine Wehus

TL;DR
This paper explores a gravity theory with spontaneous Lorentz violation via a tensor vev, leading to Goldstone modes resembling gravitons, and investigates their modified dispersion relations and observational constraints.
Contribution
It introduces a model where Lorentz symmetry is spontaneously broken in gravity, resulting in Goldstone gravitons with unique properties and potential observable effects.
Findings
Goldstone modes mimic gravitons in certain conditions
Lorentz-violating corrections modify graviton dispersion relations
Cosmic ray observations can constrain Lorentz-violating effects
Abstract
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…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
