Compact binary systems in the post-Newtonian limit of gravitational theories with preferred frames
Abstract
Gravitational-wave observations of compact-binary inspirals offer the opportunity to test deviations from general relativity in both strong and weak-field regimes. In previous work, we developed a theory-independent formalism for describing compact-binary dynamics in metric theories of gravity without preferred frames, using the parametrised post-Newtonian (PPN) couplings together with an additional set of scalar sensitivity parameters that encode violations of the strong equivalence principle. Here, we extend this framework to include preferred-frame effects, of the type that can arise in (for example) vector-tensor theories of gravity. This is achieved by introducing a time-like vector field that identifies the preferred frame, and then by allowing compact body masses to depend on the invariant formed from this field and the body's four-velocity. We calculate the modified equation of motion up to first post-Newtonian order (1PN), where the preferred-frame PPN parameters α1 and α2 acquire contributions from our new vector sensitivities. We further combine scalar and vector sensitivities in a unified formalism, which we validate with an example scalar-vector-tensor theory. This approach provides the orbital dynamics required to extend gravitational-wave constraints on PPN and sensitivity parameters to theories of gravity that admit preferred frames, as well as those that do not.
Related
- Compact Core--Shell Equilibria in Gravitational Vlasov--Poisson Systems with Positive and Negative Mass
- Innermost stable circular orbit (ISCO) of arbitrary-mass compact binaries with spins at the fourth post-Newtonian order
- All Order Gravitational Wave Tails for Subleading Post-Newtonian Expansion
- Far-Zone Gravitational Interactions at the Sixth Post-Newtonian Order
- Newtonian Gravitational Curvature-Induced Entanglement Generation
BibTeX
@misc{pitt2026compact,
title = {{Compact binary systems in the post-Newtonian limit of gravitational theories with preferred frames}},
author = {Oliver Pitt and Timothy Clifton},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.12784},
eprint = {2609.12784},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.12784},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Compact binary systems in the post-Newtonian limit of gravitational theories with preferred frames
AU - Oliver Pitt
AU - Timothy Clifton
PY - 2026
DA - 2026/09/11
PB - arXiv
DO - 10.48550/arxiv.2609.12784
UR - https://arxiv.org/abs/2609.12784
AB - Gravitational-wave observations of compact-binary inspirals offer the opportunity to test deviations from general relativity in both strong and weak-field regimes. In previous work, we developed a theory-independent formalism for describing compact-binary dynamics in metric theories of gravity without preferred frames, using the parametrised post-Newtonian (PPN) couplings together with an additional set of scalar sensitivity parameters that encode violations of the strong equivalence principle. Here, we extend this framework to include preferred-frame effects, of the type that can arise in (for example) vector-tensor theories of gravity. This is achieved by introducing a time-like vector field that identifies the preferred frame, and then by allowing compact body masses to depend on the invariant formed from this field and the body's four-velocity. We calculate the modified equation of motion up to first post-Newtonian order (1PN), where the preferred-frame PPN parameters α_1 and α_2 acquire contributions from our new vector sensitivities. We further combine scalar and vector sensitivities in a unified formalism, which we validate with an example scalar-vector-tensor theory. This approach provides the orbital dynamics required to extend gravitational-wave constraints on PPN and sensitivity parameters to theories of gravity that admit preferred frames, as well as those that do not.
ER -