QUANTUM CHAOS — STADIUM BILLIARD

Bunimovich (1979): The stadium is fully chaotic — all trajectories are ergodic and mixing. Quantum mechanically, energy level spacings follow the Wigner-Dyson distribution P(s) = (π/2)s·e^(−πs²/4) (GOE), unlike integrable systems (Poisson: P(s) = e^(−s)).