Structural Gravitational Waves v1.5: Propagation Tests

This release presents v1.5 of the Structural Gravitational Waves (SGW) series, introducing an illustrative framework for investigating gravitational-wave propagation across cosmological distances. Building upon the coherent detector-network framework developed in v1.4, this version extends the SGW program from source-region analyses to propagation-sector studies. The framework includes frequency-dependent gravitational-wave speed models, modified dispersion relations, arrival-time delays, propagation-induced phase shifts, attenuation models, multi-detector and hierarchical inference, standard-siren cosmology, joint source–propagation constraints, a seven-test validation battery (P1–P7), and illustrative sensitivity forecasts for current and future detector networks (O4, O5, Cosmic Explorer, and Einstein Telescope). The repository contains: Full paper (PDF) Demonstration Python script (sgw_v15_demo.py) README documentation Important Notice This work presents an illustrative methodological framework. All numerical values, sensitivity forecasts, propagation constraints, validation results, and cosmological examples are illustrative demonstrations intended to explain the framework. They are not derived from actual LIGO–Virgo–KAGRA observations or multi-messenger data analyses. This release establishes the propagation-analysis layer of the SGW roadmap and provides the methodological foundation for v1.6: Precision Structural Tests.