The H– Ḣ Active Vacuum: A Unified Critical Framework for Emergent Spacetime, Gravity, and Cosmological Dynamics

We propose that the physical vacuum is a near-critical, dynamically coherent condensate of correlated hydrogen–antihydrogen (H–Ḣ) dipolar pairs forming a percolating quantum substrate. Spacetime, gravity, and cosmological evolution arise as macroscopic thermodynamic and elastic responses of this medium. The Einstein–Hilbert action emerges as the long-wavelength limit of the free energy functional of the substrate. The framework resolves the Hubble and S₈ tensions through scale-dependent gravitational coupling and provides a natural origin for dark energy as residual condensate enthalpy. We link cosmological observables to universal critical exponents (Df ≈ 2.86, ν ≈ 0.88, ηeff ≈ 0.14) and provide six falsifiable predictions for 2026-2030 surveys, including the rigid dark-energy relation wₐ = 6(1 + w₀) and a specific S₈(z) evolution.