Quantum objects are notoriously shifty. Take the photon, for example. The quantum of light can act as a particle one moment, following a well-defined path like a tiny projectile, and a wave the next, overlapping with its ilk to produce interference patterns, much like a ripple on the water.
Wave–particle duality is a key feature of quantum mechanics, one not easily understood in the intuitive terms of everyday experience. But the dual nature of quantum entities gets stranger still. New experiments demonstrate that photons not only switch from wave to particle and back again but can actually harbor both wave and particle tendencies at the same time. In fact, a photon can run through a complex optical apparatus and disappear for good into a detector without having decided on an identity—assuming a wave or particle nature only after it has been destroyed.
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