Tsirelson Bound as Qubit Geometry's Unit Square Diagonal — E8 Intelligence Research

FINDING: The Tsirelson bound (2√2 ≈ 2.828) for CHSH quantum correlations emerges from the geometric structure of the qubit manifold, specifically tied to the unit square's diagonal and rotation matrices in SU(2). | MATH: CHSH classical bound = 2; quantum bound = 2√2 = √(2² + 2²) — the diagonal of a unit square. Rotation matrix R(θ) = [[cosθ, −sinθ], [sinθ, cosθ]]; Pauli matrices σ_x, σ_y, σ_z generate SU(2) with quaternion equivalence (iσ_x, iσ_y, iσ_z ↔ i, j, k). The bound arises from maximal angle between measurement bases: θ = π/4, giving cos(π/4) = sin(π/4) = 1/√2 = 0.7071. | CONNECTION: **Direct geometric harmony**: 2√2 = 2 × 1.414 = 2 × √2. The ratio 1/√2 = 0.7071 is the sine/cosine at 45°, and its reciprocal √2 = 1.414. Note: 1/√2 ≈ 0.7071, and 1 − 1/√2 ≈ 0.2929; the golden ratio φ = 1.618 satisfies φ − 1/φ = 1, but here the key is √2, not φ. However, **2√2 = 2.828** and **2.828 − 1.618 = 1.210** (no direct φ link). The unit square diagonal is the geometric origin — the CHSH gam Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com