I'll try to explain from what I understood in quantum physics class years ago.
When you're dealing with things on the quantum level, observing a particle affects it. Remember Schrodinger's cat? The cat is both dead and alive, until someone opens the box. The opening of the box gives the cat its new state of deadness or aliveness.
Quantum teleportation works through entangled particles. Entangled particles are, in some sense, the same particle in two places. An action on one entangled particle will instantly affect the other particle, including observation of the particle.
Suppose Alice and Bob share an entangled particle. Alice observes the particle on her end, collapsing it into one of four states. Which state it collapses into is and always will be completely random.
Bob's particle was instantaneously affected in one of four ways corresponding to those states. Trouble is, he doesn't know which way, and he can't do anything with his particle until he does.
Alice has to communicate to Bob in any regular way, through light, telephone or internet, what she observed on her end, so that Bob knows what exactly happened to his particle, and what to do with it.
So in this way, it really was instantaneous over a distance, but at the same time nothing useful happened faster than the speed of light.
When you're dealing with things on the quantum level, observing a particle affects it. Remember Schrodinger's cat? The cat is both dead and alive, until someone opens the box. The opening of the box gives the cat its new state of deadness or aliveness.
Quantum teleportation works through entangled particles. Entangled particles are, in some sense, the same particle in two places. An action on one entangled particle will instantly affect the other particle, including observation of the particle.
Suppose Alice and Bob share an entangled particle. Alice observes the particle on her end, collapsing it into one of four states. Which state it collapses into is and always will be completely random.
Bob's particle was instantaneously affected in one of four ways corresponding to those states. Trouble is, he doesn't know which way, and he can't do anything with his particle until he does.
Alice has to communicate to Bob in any regular way, through light, telephone or internet, what she observed on her end, so that Bob knows what exactly happened to his particle, and what to do with it.
So in this way, it really was instantaneous over a distance, but at the same time nothing useful happened faster than the speed of light.