Can a quantum particle pass through a barrier taller than its own energy — a wall it classically could never cross?
▶ Launch the interactive simulationLaunch a Gaussian wavepacket at a potential barrier with energy E < V₀ and evolve the Schrödinger equation (Visscher's norm-conserving scheme); measure the probability T that ends up beyond the barrier, and compare to the rectangular-barrier formula.
T > 0 (classically T = 0 for E < V₀ — the particle always bounces) matching the tunnelling coefficient, while the total probability ∫|ψ|² stays 1 (unitary evolution)