Causal Lorentzian Theory of Gravitation Conceptual Foundations, Nonlinear Completion, and Observational Signatures

We present Causal Lorentzian Theory (CLT), a flat-spacetime, Lorentz-invariant field theory of gravitation with explicit causal propagation and exact local energy–momentum conservation. Gravitation is described as a physical field propagating on Minkowski spacetime rather than as spacetime curvature. Matter localization is governed by a conformal localization factor modifying physical clock rates and length scales, while photon propagation occurs through a nonlinear, polarizable and magnetizable quantum vacuum medium. A minimal nonlinear completion is introduced in which gravitational field self-energy acts as a physical source while the propagation operator remains linear and hyperbolic. The theory reproduces all experimentally tested weak-field predictions of General Relativity—including Mercury perihelion advance, gravitational light deflection, and Shapiro time delay—while predicting controlled, testable deviations in strong-field regimes such as photon-ring structure and strong gravitational lensing.