FINDING: E8 lattice (240 root vectors) projects to 3D icosahedral quasicrystal via quaternion orientational order parameter; solidification phase transition classified by quaternion order parameter. MATH: - E8 root system: 240 minimal vectors in 8D; 112 of form (±1,±1,0,0,0,0,0,0) and permutations, 128 of form (±½,±½,±½,±½,±½,±½,±½,±½) with even number of minus signs. - Quaternion order parameter: q ∈ ℍ (4D), normalized |q|=1, maps to SO(3) rotation via double cover SU(2). - Icosahedral group H₃: order 120, generated by quaternions representing 5-fold rotations (golden ratio φ = (1+√5)/2 ≈ 1.618). - Projection: 8D → 4D (quaternion space) → 3D via Hopf fibration or cut-and-project; yields 3D icosahedral quasicrystal with 6 fivefold axes. - Solidification order parameter: Landau-type free energy expanded in quaternion invariants; critical exponents linked to E8 root system. CONNECTION: - Golden ratio φ = 1.618 appears in icosahedral vertices: (0, ±1, ±φ) and permutations. Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com
Andrew Stewart Caldin (Tue,) studied this question.