To Send Data, Physicists Resort to Quantum Voodoo

摘要

Tabloid journalists and writers of mystical self-help works will be happy to know there is an area of physics that holds a vague resemblance to voodoo. It involves one of the weirdest of quantum-mechanical paradoxes, in which two particles can be created simultaneously with their internal quantum states--their spin, for instance, or polarization--irrevocably "entangled." Quantum mechanics dictates that until a particular state is actually measured, it has no value at all. But when a measurement is made on one entangled particle, its partner instantly takes on the opposite value, even if it happens to be halfway across the universe at the time.