The growing catalog of gravitational wave (GW) detections by the LIGO-Virgo-KAGRA Collaboration enables increasingly stringent tests of general relativity, particularly regarding possible parity and Lorentz violations. While most current analyses employ single-parameter methods, varying one deformation parameter at a time, modified gravity theories often predict multiple, coexisting deviations. In this work, we construct four specific multi-parameter GW waveform models incorporating parity- and Lorentz-violating effects and perform full Bayesian parameter estimation to compare multi-parameter and single-parameter constraints. We find that including multiple deformation parameters yields constraints on individual parameters that are generally comparable to those from single-parameter analyses, despite one specific model showing a degeneracy between the deformation parameters. Our results support the robustness of single-parameter tests for parity and Lorentz symmetry of gravity in current and future GW observations.
@article{arxiv.2507.09705,
title = {Constraints on parity and Lorentz violations from gravitational waves: a comparison between single-parameter and multi-parameter analysis},
author = {Wei-Hua Guo and Yuan-Zhu Wang and Tao Zhu},
journal= {arXiv preprint arXiv:2507.09705},
year = {2025}
}