Quantum entanglement is the mysterious phenomenon where two particles become tightly intertwined and behave as one system — whether they are next to each other on a laboratory bench, or either sides of a galaxy.
If you examine one particle and measure a certain property — say, vertical polarization — then the other will instantly adopt the opposite property — in this case, horizontal polarization.
It’s crazy stuff. Albert Einstein described it as “spooky action at a distance,” when he was still struggling to get his brain around the ideas proposed by quantum theory. But it’s a powerful phenomenon, and one that physicists have long attempted to harness in the lab.
Trouble is, creating a pair of particles with any distance between them has always been a difficult hurdle to overcome. Imperfections in optic fiber glass, or air turbulence, means that the qubits become unentangled. Plus as the distance gets farther your beam gets wider, so photons simply miss their target.
Juan Yin at the University of Science and Technology of China in Shanghai claims to have cracked it. His team sent photons between two stations, separated by 97 km. Over a Chinese lake, to be precise. To pull off this feat, Yun and friends used a 1.3 Watt laser, and a clever optic steering technique to keep the beam precisely on target. With this setup, they were able to teleport more than 1,100 photons in four hours, over a distance of 97 kilometers.
The last quantum teleportation record was 16 km, and was set by a different set of Chinese researchers in 2010.
Read more at Wired Science
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