Rational Fraction Critical Exponents and √2 in the 2D Ising Model Exact Solution — E8 Intelligence Research

FINDING: 2D Ising model critical exponents are rational fractions derived from exact solution, with √2 appearing in the spontaneous magnetization exponent. MATH: - Critical exponents: α = 0 (log divergence), β = 1/8, γ = 7/4, δ = 15, ν = 1, η = 1/4 - Spontaneous magnetization: M ∝ (T_c - T)^β, β = 1/8 = 0.125 - Correlation length exponent: ν = 1 - Susceptibility exponent: γ = 7/4 = 1.75 - Specific heat exponent: α = 0 (logarithmic) - Exact solution via Onsager (1944): free energy expressed in terms of elliptic integrals, critical temperature T_c = 2/ln(1+√2) ≈ 2.269 J/k_B - √2 appears in T_c formula and in β = 1/8 (since 1/8 = (1/2)^3, but deeper: β = 1/8 emerges from algebraic order parameter scaling involving √2 in the lattice combinatorics) CONNECTION: - β = 1/8 = 0.125 is a rational fraction, not directly a golden ratio, but the critical temperature T_c = 2/ln(1+√2) involves √2, linking to square lattice symmetry (crystallographic point group D4). - The exponent Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com