with α α and β β the probability amplitudes for the states | H ⟩ ⟩ and | V ⟩ ⟩ respectively. When the photon's polarization is measured, the resulting state is either horizontal or vertical. But in a random experiment, the probability of being horizontally polarized is | α α | 2 , and the probability of being vertically polarized is | β β | 2 .