'''Quantum entanglement''' is the phenomenon of two (or more) [[Subatomic particle|particles]] relating to each other in a certain manner under the special rules of [[Quantum mechanics]], as in taking spins opposite to each other. When they are separated they retain the same opposite spins, and the observation of the spin of one of the particles always obtains the opposite spin for the other particle, even though they may have been separated from each other by many miles. This phenomenon lies outside of normal intuition. Physicists refer to the normal state of affairs as "[[local realism]]". Strict quantum mechanics is sometimes at odds with local realism, and entanglement is an example of that. | '''Quantum entanglement''' is the phenomenon of two (or more) [[Subatomic particle|particles]] relating to each other in a certain manner under the special rules of [[Quantum mechanics]], as in taking spins opposite to each other. When they are separated they retain the same opposite spins, and the observation of the spin of one of the particles always obtains the opposite spin for the other particle, even though they may have been separated from each other by many miles. This phenomenon lies outside of normal intuition. Physicists refer to the normal state of affairs as "[[local realism]]". Strict quantum mechanics is sometimes at odds with local realism, and entanglement is an example of that. |