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

Abstract We propose that the physical vacuum is a near-critical, dynamically coherent condensate of correlated hydrogen–antihydrogen (H–$\dot{H}$) 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 $S_8$ 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 ($D_f \approx 2.86$, $\nu \approx 0.88$, $\eta_{eff} \approx 0.14$) and provide six falsifiable predictions for 2026-2030 surveys, including the rigid dark-energy relation $w_a = 6(1 + w_0)$ and a specific $S_8(z)$ evolution.