coherence science definition

A property holding for two or more waves or fields when each individual wave or field is in phase with every other one. Lasers, for example, emit almost perfectly coherent light; all the photons emitted by a laser have the same frequency and are in phase. Since quantum states can be described by a wave equation , coherence can hold for quantum states in general, though only among bosons. Coherence is generally possible in physical systems that may undergo superposition . Maintaining coherence of light is important in fiber optic communications. See also Bose-Einstein condensate.