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Abstract As the gravitational-wave (GW) detector network is upgraded and the sensitivity of the detectors improves, novel scientific avenues open for exploration. For example, tests of general relativity (GR) will become more accurate as smaller deviations can be probed. Additionally, the detection of lensed GWs becomes more likely. However, these new avenues could also interact with each other, and a GW event presenting deviations from GR could be mistaken for a lensed one. Here, we explore how phenomenological deviations from GR or binaries of exotic compact objects could impact those lensing searches focusing on a single event. We consider strong lensing, millilensing, and microlensing, and find that certain phenomenological deviations from GR may be mistaken for all of these types of lensing. Therefore, our study shows that future candidate lensing events would need to be carefully examined to avoid a false claim of lensing where instead a deviation from GR has been seen.
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This content will become publicly available on February 13, 2026
Possible causes of false general relativity violations in gravitational wave observations
General relativity (GR) has proven to be a highly successful theory of gravity since its inception. The theory has thrivingly passed numerous experimental tests, predominantly in weak gravity, low relative speeds, and linear regimes, but also in the strong-field and very low-speed regimes with binary pulsars. Observable gravitational waves (GWs) originate from regions of spacetime where gravity is extremely strong, making them a unique tool for testing GR, in previously inaccessible regions of large curvature, relativistic speeds, and strong gravity. Since their first detection, GWs have been extensively used to test GR, but no deviations have been found so far. Given GR’s tremendous success in explaining current astronomical observations and laboratory experiments, accepting any deviation from it requires a very high level of statistical confidence and consistency of the deviation across GW sources. In this paper, we compile a comprehensive list of potential causes that can lead to a false identification of a GR violation in standard tests of GR on data from current and future ground-based GW detectors. These causes include detector noise, signal overlaps, gaps in the data, detector calibration, source model inaccuracy, missing physics in the source and in the underlying environment model, source misidentification, and mismodeling of the astrophysical population. We also provide a rough estimate of when each of these causes will become important for tests of GR for different detector sensitivities. We argue that each of these causes should be thoroughly investigated, quantified, and ruled out before claiming a GR violation in GW observations.
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- PAR ID:
- 10583042
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Editor(s):
- NA
- Publisher / Repository:
- SciPost
- Date Published:
- Journal Name:
- SciPost Physics Community Reports
- ISSN:
- 0000-0000
- Subject(s) / Keyword(s):
- Tests of General Relativity
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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