Changing the phase of a wave-function wave-function is a probability amplitude in quantum mechanics describing the quantum state of a particle and how it behaves. when we change the phase of a wave-function what are we changing? are we changing the probability distribution wrt time-space? the change in phase (between the wave-functions travelling different paths) causes the changes in interference pattern is any energy required to change the phase of a wave-function? or when a wave-function changes phase is there an exchange of energy (with the instrument that caused the phase change)?