Wavefunction Collapse & Born Rule

|ψ(x)|² — Probability Density

Born Rule Weights |cₙ|²

Re[ψ(x)] — Real Part (Oscillating)

Measurement History

Quantum Measurement Postulate: Before measurement, a particle exists in superposition ψ = Σ cₙφₙ where {φₙ} are energy eigenstates. The Born Rule states that the probability of measuring eigenvalue Eₙ is |cₙ|². Upon measurement, the wavefunction collapses instantaneously to the eigenstate φₙ — all other probability amplitude vanishes. This non-unitary collapse is the central mystery of quantum mechanics. Click "Measure!" repeatedly to see the Born Rule statistics emerge from many trials.