Revisiting the cuscuton as a Lorentz-violating gravity theory
Abstract
The cuscuton is a scalar field with infinite speed of propagation. It was introduced in the context of cosmology but it has also been claimed to resemble Hořava gravity in a certain limit. Here we revisit the cuscuton theory as a Lorentz-violating gravity theory. We clarify its relation with Hořava gravity and Einstein-æther theory, analyze its causal structure, and consider its initial value formulation. Finally, we discuss to which extent the cuscuton theory can be used as a proxy for Hořava gravity in the context of gravitational collapse and formation of universal horizons.
- Publication:
-
Physical Review D
- Pub Date:
- March 2018
- DOI:
- 10.1103/PhysRevD.97.064020
- arXiv:
- arXiv:1612.01824
- Bibcode:
- 2018PhRvD..97f4020B
- Keywords:
-
- High Energy Physics - Theory;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- General Relativity and Quantum Cosmology
- E-Print:
- 9 pages, revised version as published in PRD