Holographic Dark Energy Series (Papers I–IV): A Parameter-Free Geometric Derivation of Dark Energy and Dark Matter from the Causal Horizon of De Sitter Spacetime

Holographic Dark Energy Series — Complete Collection (Papers I–IV) April 2026 | Yiling Zhu | Independent Researcher, London Paper I: An Analytical Expression for the Dark Energy Density Fraction from Holographic UV/IR Coupling → C₀ = π²/(16e²), Ω_Λ = π³/(6e²) ≈ 0.6994, deviation 0.06% from PDG Paper II: Physical Interpretation and Scope of the Holographic Coefficient C → UV = π²/16 (spherical phase space), IR = 1/e² (light-cone ratio) Paper III: From Casimir Cavities to the Cosmological Horizon — A Unified Geometric Constraint (Revised) → C(R,τ) = (π²/16)·(lP/R)²·e^(−2τ), spanning 61 orders of magnitude. Spherical Casimir repositioned as equal candidate vs Boyer. Paper IV: Dark Matter from Holographic Supersaturation → Ω_DM = π⁴(√4π−e)/(6e⁴) ≈ 0.2458, DESI DR2 comparison, fσ₈ prediction Core result: Dark energy and dark matter share a single geometric origin — the causal horizon of de Sitter spacetime. Zero free parameters throughout.