Nuclear Spins in Posner Molecules as Quantum Substrate for Brain Processing — E8 Intelligence Research

FINDING: Matthew Fisher's quantum cognition hypothesis proposes nuclear spins of phosphorus atoms in Posner molecules (Ca₉(PO₄)₆) as the physical substrate for quantum processing in the brain, with a specific focus on spin-1/2 dynamics and decoherence timescales. | MATH: Phosphorus-31 nuclear spin I = 1/2; Posner molecule Ca₉(PO₄)₆ has 6 phosphate groups → 6 phosphorus spins; key timescale: T₂ (spin coherence) ~ 10⁻³–10⁻¹ s at physiological temperatures; proposed quantum gate: controlled NOT (CNOT) via dipolar coupling between adjacent ³¹P spins; entanglement lifetime τ_ent ~ 10⁻⁴–10⁻³ s; Fisher's key constraint: decoherence rate Γ < 1/τ_ent for quantum error correction; spin-spin coupling J ~ 10–100 Hz (weak, but sufficient for quantum gates if shielded); the "quantum error threshold" ~ 10⁻⁴ per gate operation (standard threshold theorem). | CONNECTION: Posner molecule Ca₉(PO₄)₆ exhibits octahedral symmetry (O_h point group) — the phosphate groups sit at vertices of a near-regular oct Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com