Slashdot Mirror
Chinese Satellite Breaks Distance Record For Quantum-Key Exchange (sciencemag.org)
slew writes: Science Magazine reports a team of physicists using the Chinese Micius satellite (launched back in August 2016) have sent quantum-entangled photons from a satellite to ground stations separated by 1200 kilometers, smashing the previous world record. Sending entangled photons through space instead of optical fiber networks with repeaters has long been the dream of those promoting quantum-key exchange for modern cryptography. Don't hold your breath yet, as this is only an experiment. They were only able to recover about 1000 photons out of about 6 billion sent and the two receiving stations were on Tibetan mountains to reduce the amount of air that needed to be traversed. Also the experiment was done at night to minimize interference from the sun. Still, baby steps... Next steps for the program: a bigger satellite for more power and moving to quantum teleportation instead of simple key exchange. The results of the experiment were published in the journal Science.
Mods, before modding this up, be aware the poster(s) posts the same misunderstood garbage to nearly every Slashdot story involving anything quantum mechanics related. The poster fundamentally misunderstands entanglement experiments and the variety of possible setups that have been in use for decades now. Yet the poster always disregards any detailed and/or cited reply showing how wrong it is, while taking time to attack others replies that are less intelligent and acting as if that validates their armchair disproof of quantum mechanics. Mean while, those with backgrounds in the subject realize it is a waste of time trying to correct the same mistakes when it gets spammed on so many articles, and yield not because the parent is correct, but because the parent has too much free time and is too dense to argue with.
RTFA. Or if you can't, I'll summarize.
The satellite generated entangled photon pairs, sending them down to two separated ground stations in the Himalayas.
One out of every 6 million pairs was received properly (how they could tell, I don't know. Time codes?). Polarization measured at each ground station and correlated (via normal phone or perhaps Internet). Correlation was nonrandom due to Bell's Inequality, demonstrating that entanglement survived the transmission from space.