Holographic Photon-Entropy Coupling and DESI DR2: Direct Validation of \alpha-Derived Cosmological Predictions

We present a holographic impedance framework in which cosmological observables are derived from the fine-structure constant α (a fundamental QED constant) and the measured Hubble scale H₀ (used as an observational boundary condition, not a fitted parameter). No cosmological parameters are adjusted to match data. The coupling structure—governed by α^(3/2) from vacuum impedance matching at the holographic boundary—yields the following predictions without fitted parameters: (i) Hubble tension magnitude √α = 8.54%; (ii) dark energy timescale τ_eff = 1/(α^(3/2)H₀) = 23.27 Gyr; (iii) an emergent effective equation-of-state baseline w₀ = −1 + 3√α = −0.744, distinct from standard CPL parameterizations; (iv) matter density Ω_m = 0.299 via lattice geodesic partitioning; (v) expansion rate enhancement ΔH/H = +1.15% at z ~ 2 relative to the Planck ΛCDM baseline; and (vi) phantom crossing at z ≈ 0.54, which lies in the redshift range where DESI DR2 indicates preference for dynamical dark energy with w < −1. All five quantitative predictions lie within observational uncertainties against DESI DR2 (2025) and DES Y6 (2026), with deviations from 0.15σ to 0.75σ and total χ² = 0.83 (reduced χ² = 0.17). The framework additionally predicts a deceleration of expansion in z ∈ [0.955, 1.484], consistent with Yang et al. (2026).