Causality in gravitational theories with second order equations of motion

Abstract

This paper studies, in a gauge invariant manner, general diffeomorphism invariant theories of gravity coupled to matter, with second order equations of motion. Causality is shown to be governed by a sextic polynomial that factorizes into a quartic and a quadratic, the former, related to the fastest degrees of freedom, is associated with purely gravitational polarizations whilst the latter pertains to a mixture of gravitation and scalar field polarizations. This work defines the basic notion of causality and of dynamical black holes in these generic theories.

Topics & Concepts