Measurement as Phase-Locking: Stern-Gerlach Sequence Δ 1 t < 0 Approach arbitrary Δ orientation precessing at ω_internal B ∇B Δ τ 2 t = 0 Field onset torque engages boundary nutation begins Δ₊ oscillates vortex density adjusting 3 0 < t < τ_lock Nutation system searching for allowed eigenstate Δ_z m = +½ or m = −½ 4 t > τ_lock Locked eigenstate selected boundary reorganized t < 0 t = 0 nutation τ_lock |Δ₊| → 0 Δ_z ±ℏ/2 Measurement is not instantaneous collapse — it is physical phase-locking on the Compton timescale (~10⁻²¹ s).