Evolution and spherical collapse in Einstein-Æther theory and Hořava gravity

Bhattacharyya, Jishnu and Coates, Andrew and Colombo, Mattia and Sotiriou, Thomas P. (2016) Evolution and spherical collapse in Einstein-Æther theory and Hořava gravity. Physical Review D, 93 (6). 64056/1-64056/10. ISSN 2470-0029

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Abstract

We compare the initial value formulation of the low-energy limit of (nonprojectable) Hořava gravity to that of Einstein-æther theory when the æther is assumed to be hypersurface orthogonal at the level of the field equations. This comparison clearly highlights a crucial difference in the causal structure of the two theories at the nonperturbative level: in Hořava gravity evolution equations include an elliptic equation that is not a constraint relating initial data but needs to be imposed on each slice of the foliation. This feature is absent in Einstein-æther theory. We discuss its physical significance in Hořava gravity. We also focus on spherical symmetry, and we revisit existing collapse simulations in Einstein-æther theory. We argue that they have likely already uncovered the dynamical formation of a universal horizon and that they can act as evidence that this horizon is indeed a Cauchy horizon in Hořava gravity.

Item Type: Article
Additional Information: © 2016 American Physical Society
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Mathematical Sciences
University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1103/PhysRevD.93.064056
Depositing User: Eprints, Support
Date Deposited: 21 Dec 2016 13:19
Last Modified: 13 Oct 2017 20:40
URI: http://eprints.nottingham.ac.uk/id/eprint/39494

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