One fascinating consequence of quantum mechanics is the strange phenomenon of entanglement, in which observing the state of one entangled particle determines the state of another in a completely different location. This effect can be harnessed by quantum computers to perform powerful calculations.
The theory of quantum mechanics was constructed in response to the surprising results of many experiments, including the famous double slit experiment. Quantum mechanics is currently the most accurate theory for describing the motions and interactions of fundamental particles. Among the many surprising predictions of quantum mechanics are wave-particle duality and quantum entanglement.