Beyond Lorentz Symmetry : A Response Delay Model Encompassing Relativity and Gravito-Kinematic Optical Tests

This paper presents the response delay model (RDM), a phenomenological framework proposing that the universal speed limit of light is fundamentally governed by an information-exchange limit restricted by the density of the quantum vacuum. We derive a generalized directional delay equation and show that the classic Lorentz factor of special relativity (SR) emerges as its transverse limit (a special case at a propagation angle of ). By evaluating the longitudinal case (), the RDM predicts a measurable symmetry-breaking propagation anisotropy. For a low Earth orbit (LEO) satellite traversing this vacuum density, the RDM calculates a fractional frequency shift of between orthogonal optical paths. We explicitly resolve the paradox of why this phenomenally large signal has evaded detection: historical space-borne tests exclusively utilize scalar atomic clocks that isotropically mask geometric anisotropy, while ground-based optical cavity tests co-move with the gravitationally entrained vacuum ( ). Conditioned strictly upon the experimental confirmation of this unexplored gravito-kinematic anisotropy via purely optical space-based tests, the RDM can be interpreted as encompassing both SR and general relativity (GR) under a single physical framework of constant-speed information exchange restricted by vacuum density.