Graviton propagation in ghost-free massive gravity

Claudia de Rham; Jan Kożuszek; Andrew J. Tolley; Toby Wiseman

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arXiv · 2604.22418

Graviton propagation in ghost-free massive gravity

Claudia de Rham·Jan Kożuszek·Andrew J. Tolley·Toby Wiseman

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Abstract

We consider the ghost-free dRGT massive gravity with two of its three possible mass terms. This theory has five gravitational degrees of freedom. On Minkowski spacetime these modes have helicity-2, -1 and -0 and propagate on the Minkowski lightcone in the high-frequency limit. However for a general background the degrees of freedom corresponding to the helicity-1 and -0 modes have characteristics different to that of the metric lightcone. Here we prove in all generality, that the two degrees of freedom corresponding to the helicity-2 mode always propagate on the metric lightcone for any background in the high-frequency limit, which has significant relevance for current and future observational tests of the theory.

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Claudia de Rham, Jan Kożuszek, Andrew J. Tolley, Toby Wiseman. 2026-04-24. Graviton propagation in ghost-free massive gravity. https://arxiv.org/abs/2604.22418

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