Scale Self-Duality Invariance and Closed 3-Sphere Universe

This paper constructs a fully geometric unified theory of fundamental physics based on two first principles: Scale Self-Duality Invariance and the closed 3-sphere cosmic topology. The theory achieves a self-consistent unification of general relativity and quantum mechanics, naturally deriving the Einstein field equations and the complete gauge group structure of the Standard Model of particle physics without introducing extra dimensions, free parameters, or artificial assumptions. It elucidates the geometric origins of fermion spin, the Pauli exclusion principle, charge quantization, and inertial mass, and provides a self-consistent explanation for dark matter, dark energy, and the accelerated expansion of the universe. The theory reconstructs the spacetime geometric roots of quantum phenomena, fundamentally eliminating the divide between the macroscopic and microscopic, classical and quantum realms. Multiple falsifiable quantitative predictions are presented, which can be verified by astronomical observations and particle physics experiments.