Causal properties of nonlinear gravitational waves in modified gravity

Arthur George Suvorov and Andrew Melatos
Phys. Rev. D 96, 064032 – Published 21 September 2017

Abstract

Some exact, nonlinear, vacuum gravitational wave solutions are derived for certain polynomial f(R) gravities. We show that the boundaries of the gravitational domain of dependence, associated with events in polynomial f(R) gravity, are not null as they are in general relativity. The implication is that electromagnetic and gravitational causality separate into distinct notions in modified gravity, which may have observable astrophysical consequences. The linear theory predicts that tachyonic instabilities occur, when the quadratic coefficient a2 of the Taylor expansion of f(R) is negative, while the exact, nonlinear, cylindrical wave solutions presented here can be superluminal for all values of a2. Anisotropic solutions are found, whose wave fronts trace out time- or spacelike hypersurfaces with complicated geometric properties. We show that the solutions exist in f(R) theories that are consistent with Solar System and pulsar timing experiments.

  • Figure
  • Figure
  • Figure
  • Received 16 March 2017

DOI:https://doi.org/10.1103/PhysRevD.96.064032

© 2017 American Physical Society

Physics Subject Headings (PhySH)

Gravitation, Cosmology & AstrophysicsNonlinear Dynamics

Authors & Affiliations

Arthur George Suvorov*

  • School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia

Andrew Melatos

  • School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia and Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav)

  • *suvorova@student.unimelb.edu.au
  • amelatos@unimelb.edu.au

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 96, Iss. 6 — 15 September 2017

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review D

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×