What is interference

Interference is the process in which two or more light, sound, matter waves or electromagnetic waves combine to reinforce (constructive interference) or cancel each other (destructive interference), the amplitude of the resulting wave being equal to the sum of the amplitudes of the combining waves.

Because of the wave-particle duality, every particle of every kind is also described by wave properties. Interference between the waves associated with these particles is thus possible.

Interference brings all the particles in the same quantum state, making their collective behaviour identical.

Interference thus creates order out of disorder, the initial independent behaviour becomes correlated.





(photo source: http://www.olympusmicro.com/primer/lightandcolor/interference.html)