Bell's Inequality & Quantum Non-locality

About Bell's Inequality

Bell's inequality provides a way to test whether quantum mechanics' predictions can be explained by local hidden variable theories. Quantum mechanics violates Bell's inequality, proving that nature exhibits non-local correlations.

Alice Angle 1 (°) 0°

Alice Angle 2 (°) 45°

Bob Angle 1 (°) 22.5°

Bob Angle 2 (°) 67.5°

Entangled Photon Pairs Experiment

E(a₁,b₁)

-0.707

E(a₁,b₂)

-0.707

E(a₂,b₁)

-0.707

E(a₂,b₂)

0.707

Bell Parameter S

2.83

|E(a₁,b₁) - E(a₁,b₂) + E(a₂,b₁) + E(a₂,b₂)|

Classical Limit

2.00

Bell's Inequality: S ≤ 2

Quantum Maximum

2√2 ≈ 2.83

Tsirelson's bound

Bell's Inequality is VIOLATED! Quantum mechanics exhibits non-local correlations.