We show that both Special and General Relativity emerge as limiting forms of a single Lorentz-invariant standing-wave operator defining Quantum Wavespace Theory (QWST). In this framework, the gravitational effects described by Einstein as spacetime curvature can be modeled equivalently as spatial variations in the local phase velocity within a Lorentz-invariant standing-wave field, with geodesics corresponding to Fermat paths in the effective refractive index. The weak-field limit reproduces the standard relativistic tests—gravitational redshift, light deflection, Shapiro delay, and perihelion precession—while the strong-field ``event-shell'' condition yields a horizon radius identical to the Schwarzschild value but with a finite interior pressure, avoiding divergent metric conditions. At cosmological scales, the same refractive-metric formulation reproduces Hubble and CMB parameters and suggests a minimal link between gravitational and dark-energy densities through a single leakage coefficient. Together these results indicate that SR, GR, and quantum behavior can be viewed as successive limits of one Lorentz-invariant standing-wave geometry.

Keywords:Quantum Wavespace Theory, relativity, general relativity, quantum mechanics, vacuum structure, gravitational constant, dark energy, cosmology, fundamental constants