Citation

BibTex format

@article{Menadeo:2026:09/092,
author = {Menadeo, N and Giardino, S and Zumalacárregui, M},
doi = {09/092},
journal = {Journal of Cosmology and Astroparticle Physics},
title = {Gravitational-wave dispersion over inhomogeneous space-times: general relativity, screened theories of gravity and non-minimal dark energy},
url = {http://dx.doi.org/10.1088/1475-7516/2026/09/092},
volume = {2026},
year = {2026}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Gravitational waves (GWs) are direct probes of cosmological gravity, sensitive to space-time inhomogeneities along their propagation. The presence of massive objects breaks homogeneity and isotropy, allowing for new interactions between different GW polarizations, and opening up the intriguing opportunity to test modified gravity theories. This setup generalizes the notion of gravitational deflection and lensing, revealing novel phenomena in modified theories. Any non-minimal theory introduces effective mass terms for GWs, causing lens-induced dispersion (LID), a frequency-dependent phase shift on the waveform. We compute GW dispersion in Einstein's general relativity (GR) for a spherical matter distribution, finding a small but non-zero phasing that may be constrained by existing and upcoming data. We then extend our analysis to scalar-tensor theories, focusing on symmetron gravity as an example of screened theory, combining cosmological deviations and consistency with local gravity tests. We find enhanced GW dispersion in a large region of the symmetron parameter space, compared to both GR and Brans-Dicke theory. We argue that dispersion, associated to an effective mass for the metric fluctuations, can in some cases prevent the propagation of GWs through some astrophysical bodies, turning them into reflectors. Applying this criterion to near-field lenses such as the Earth or the Moon, it is possible to identify regions of the symmetron parameter space with large dispersive effects. The richness and universality of dispersive phenomena in non-minimal theories open a new avenue to test theories of dynamical dark-energy, relevant in light of recent observational results challenging the ΛCDM paradigm.
AU  - Menadeo,N
AU  - Giardino,S
AU  - Zumalacárregui,M
DO  - 09/092
PY  - 2026///
TI  - Gravitational-wave dispersion over inhomogeneous space-times: general relativity, screened theories of gravity and non-minimal dark energy
T2  - Journal of Cosmology and Astroparticle Physics
UR  - http://dx.doi.org/10.1088/1475-7516/2026/09/092
VL  - 2026
ER  -
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