Chinese Researchers Quantum Teleport Photons Over 60 Miles
Alex Knapp
Forbes
Since 1997, researchers have been able to quantum teleport photons with a major record being set by researchers at the University of Science and Technology of China in Shanghai. In 2010, that team successfully teleported a photon over 16km. Now that same team has released new findings, in which they claim to have teleported photons nearly 100km, or over 60 miles.
Now, quantum teleportation isn’t quite the same thing as the teleportation in Star Trek. When researchers teleport a photon, they aren’t teleporting the actual photon, but rather the information contained in it through quantum entanglement. In essence, the second photon at the end of the teleport becomes the first one – or at least, it becomes an identical qubit of information. So the information is exchanged without actually travelling through the intervening distance.
(If that sounds bizarre and frightening, you’re in good company. Albert Einstein understatedly called the process of quantum entanglement “spooky action at a distance.”)
The challenge for quantum teleportation is that it has to be done in free space. Fiberoptics don’t work, because once you get to distances over about 1 kilometer, the fiber absorbs so much light that the information is lost. But while a fiberoptic cable can keep photons focused, moving over free space means using lasers – which inevitably causes the beam of light to spread out over time. However, using a powerful laser along with some other optical equipment, the researchers here developed a technique to keep the beam focused over the course of 97km, and successfully achieved quantum teleportation.
The ability to teleport information means that it could be possible to have worldwide communications that are impossible to listen in on. Because in quantum teleportation, the information doesn’t travel over any intervening distances, there’s no way to tap into the communication. As Technology Review notes, “these guys clearly have their eye on the possibility of satellite-based quantum cryptography which would provide ultra secure communications around the world.”