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❝ In a landmark study, a team of Chinese scientists using an experimental satellite has tested quantum entanglement over unprecedented distances, beaming entangled pairs of photons to three ground stations across China — each separated by more than 1,200 kilometers. The test verifies a mysterious and long-held tenet of quantum theory, and firmly establishes China as the front-runner in a burgeoning “quantum space race” to create a secure, quantum-based global communications network — that is, a potentially unhackable “quantum internet” that would be of immense geopolitical importance…
❝ The concept of quantum communications is considered the gold standard for security, in part because any compromising surveillance leaves its imprint on the transmission. Conventional encrypted messages require secret keys to decrypt, but those keys are vulnerable to eavesdropping as they are sent out into the ether. In quantum communications, however, these keys can be encoded in various quantum states of entangled photons — such as their polarization — and these states will be unavoidably altered if a message is intercepted by eavesdroppers.
❝ Ground-based quantum communications typically send entangled photon pairs via fiber-optic cables or open air. But collisions with ordinary atoms along the way disrupt the photons’ delicate quantum states, limiting transmission distances to a few hundred kilometers. Sophisticated devices called “quantum repeaters” — equipped with “quantum memory” modules — could in principle be daisy-chained together to receive, store and retransmit the quantum keys across longer distances, but this task is so complex and difficult that such systems remain largely theoretical.
Poisonally, I don’t doubt the NSA and other federal alphabet spooks are trying both methods and more. They have an endless supply of taxpayer dollar$.
Distilled entanglement brings long-distance quantum communication closer https://arstechnica.com/science/2017/06/researchers-distill-entanglement-between-qubits-age-limit-checks-in-place/