QUANTUM KICKED ROTOR

Kicks applied0
⟨p²⟩ quantum0
⟨p²⟩ classical0
Localization ξ
Floquet operator:
U = e^{-ip²T/2ℏ} · e^{-iKcos(θ)/ℏ}

Classical: diffusive ⟨p²⟩ ≈ Dt
D ≈ K²/2 (K≫1)

Quantum: dynamical localization
ψ(n) ~ e^{-|n|/ξ} (ξ ∝ D/ℏ²)