Physics
The kicked rotor is governed by:
H = p²/2 + K cos(θ) Σ δ(t−n)
Classically: For K > 0.97 (Chirikov threshold), motion is chaotic and ⟨p²⟩ ∝ t (diffusion).
Quantum: Interference freezes diffusion after a localization time t* ~ ξ. ⟨p²⟩ saturates — dynamical localization, analogous to Anderson localization in 1D.
Localization length: ξ ~ K²/2ℏ²