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Concept in quantum mechanics / From Wikipedia, the free encyclopedia
Wave–particle duality is the concept in quantum mechanics that quantum entities can have both particle and a wave properties according to the experimental circumstances. It expresses the inability of the classical concepts "particle" or "wave" to fully describe the behavior of quantum objects. As Albert Einstein wrote:[1]
It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do.
Waves are familiar in many systems, for instance water on a lake. Particles are also common, for instance projectiles from a gun. Both of these examples are at the macroscopic scale of meters. Quantum systems are for too small to see but either wave or particle behaviors can be observed depending on our method of measurement.[2]: 356 Duality does not tell us what quantum systems "really are"; duality is not an interpretation of quantum mechanics, instead it says that no language from classical macroscopic physics can explain the totality of quantum behavior;[3]: 42 quantum entities are not classical waves, classical particles, and they are not both.[4]: III:1-1