Cascade Cosmology from the String Landscape

This paper embeds the holographic vacuum evolution framework — developed in Papers I and II to explain anomalies in JWST early galaxies, DESI expansion history, galactic rotation curves, and supermassive black hole growth — into Type IIB string theory via the Large Volume Scenario. An explicit construction on the Calabi-Yau manifold P⁴₍₁, ₁, ₁, ₆, ₉₎ requires only two distinct minima in the Kähler moduli potential: an inert small-volume state and an activated large-volume basin, generated by standard LVS ingredients plus Berg–Haack–Pajer loop corrections. Phase 1 is Coleman–De Luccia tunnelling (B₁ ≈ 263, generic for nearby de Sitter transitions) ; Phase 2 is not a second tunnelling event but deterministic classical axion roll within the activated basin, with timing set by Hubble damping. This simplifies the required landscape construction from three minima to two. The central result is a geometric proof that Standard Model gauge couplings and mass ratios are exactly protected during vacuum transitions, while only the gravitational acceleration scale evolves — resolving the most serious theoretical objection to the framework. Critical damping of the axion roll locks the axion mass to m_θ ~ 10⁻³³ eV, predicting an asymmetric mountain profile with no sub-structure. The framework passes all current swampland consistency checks, and holographic equipartition identifies a zero-parameter epoch at z ≈ 11. 2 that acquires physical significance as the completion of holographic activation — an epoch with no role in ΛCDM. The paper introduces "cascade cosmology" — the idea that the post-inflationary universe undergoes a sequence of vacuum transitions whose observational signatures become progressively more accessible as the universe cools and becomes transparent.