In physics, coherence is a property of waves, that enables stationary (i.e. temporally and spatially constant) interference. More generally, coherence describes all correlation properties between physical quantities of a wave.
When interfering, waves add constructively or subtract destructively, depending on their relative phase. Two waves are said to be coherent if they have a constant relative phase, which also implies that they have the same frequency. The degree of coherence is measured by the interference visibility, a measure of how perfectly the waves can cancel due to destructive interference.
http://en.wikipedia.org/wiki/Coherence_(physics)
Νομίζω ότι λέγεται συμφωνία κυμάτων. Δείτε κι
αυτό.
Υ.Γ. ∆ύο κύµατα είναι σύµφωνα (coherent), όταν η διαφορά φάσης τους είναι ανεξάρτητη του χρόνου. Από
εδώ.