Wavefunction Collapse from Spin^c Holonomy: Paper VII in MEF Series

The quantum measurement problem — the question of why linear, unitary quantum mechanics yields definite measurement outcomes — has remained open since its formulation in 1927. Existing approaches either postulate collapse (Copenhagen), eliminate it (Everett), or parametrise it phenomenologically through free parameters (GRW spontaneous localisation, Penrose objective reduction). None derive it from the geometry of spacetime. This paper demonstrates that wavefunction collapse is a deterministic geometric process: the relaxation of metric tension across the T²/ℤ₂ orbifold sector of the K₈ manifold within the twelve-dimensional Master Equation framework. The metric stiffness S(𝒬) — comprising both the Randall–Sundrum warp factor and the Spin^c gauge flux energy — determines a corrected collapse timescale: where 𝒬 = ω(ψ − ψ̄)² is the Quantum Coherence Dilaton. This formula produces three distinct regimes without free parameters: an isolated electron (𝒬 → 0) maintains coherent superposition for ∼10¹⁶ τ_Pl; macroscopic inert matter collapses on a power-law timescale τ_coll ∝ 1/𝒬 driven by the Spin^c flux; a high-𝒬 system undergoes effectively instantaneous actualisation at the Planck scale (a geometric Zeno effect). The Born probability rule P_i ∝ |ψ_i|² is proved to be preserved exactly under the Spin^c quarter-period holonomy eiπ/2: the phase cancels identically in the modulus squared. The principal falsifiable prediction is a complexity wall — a sharp, non-linear drop in coherence time at a critical system complexity, distinguishable from the smooth exponential decay of standard environmental decoherence. The same Spin^c flux that stabilises the vacuum and yields Λ_eff ≈ 10⁻¹²² M_Pl⁴ (Paper IV) sets the stiffness profile governing collapse.