Amazing World of Quantum Entanglement

Einstein called it “spooky action at a distance,” but today quantum entanglement is poised to revolutionize technology from computers to cryptography. Physicists have gradually become convinced that the phenomenon—two subatomic particles that mirror changes in each other instantaneously over any distance—is real. But a few doubts remain. NOVA follows a ground-breaking experiment in the Canary Islands to use quasars at opposite ends of the universe to once and for all settle remaining questions. Scientists are working to decipher and harness the power of quantum mechanics, but the strange nature of entanglement and other quantum phenomena continues to confound researchers, posing new and mystifying questions.


From an experiment studying quasars at opposite ends of the universe to probing the interactions of elementary particles, researchers are gathering insights that could shatter the laws of space and time and provide a radical new understanding of the universe.

This documentary presents cutting-edge work and considers various implications of the coming quantum revolution that begins with making sense of the seemingly absurd.

By entangling particles on a satellite and shooting them down to Earth, China may have just set the tone for a global “quantum space race.”

In a new study in the journal Science, Jian-Wei Pan, a physicist at the University of Science and Technology of China in Shanghai, and his colleagues report that they were able to entangle photons aboard a satellite 300 miles above Earth and then beam those particles to three ground stations across China—each separated by more than 700 miles.

It’s an unprecedented feat. Not only were the particles entangled in space (scientists have never done this before), but they retained their bizarre connection even after they’d been separated by a distance 10 times the previous record for what’s called “quantum teleportation.”

Entanglement still boggles physicists’ minds to this day, even though our understanding of it has its origins in the renaissance of early 20th-century quantum theory research. According to quantum mechanics, particles can be in different “states” at once, and when they’re observed, those superimposed states collapse into just one. When particles are “entangled,” their states are linked together across space—when the one particle is measured, the other particle’s properties become frozen as well. Einstein wasn’t a fan of this idea because it suggested that communication between particles could travel instantaneously—i.e., faster than the speed of light.

Though it sounds like a pointless exercise to make “twin” particles and send them careening away from each other, scientists are doing just that in order to pioneer what’s called “quantum communication,” an ultra-private way of sending messages. Because observation of one entangled particle immediately affects its partner, information sent via quantum methods can’t be hacked without it being very obvious to the other party involved.

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