A quantum system evolving under H continuously collapses back to its initial state when measured frequently enough.
Survival probability after N measurements in time T: P = [cos²(ΩT/2N)]^N → 1 as N→∞
Key insight: between measurements, P(survive) ≈ 1 − (ΩΔt)². After N measurements: P ≈ [1 − (ΩT/N)²]^N → exp(−Ω²T²/N) → 1
Anti-Zeno effect: some measurement rates accelerate decay.