Quantum entanglement is the phenomenon of two particles, such as photons, that remain connected even when they are separated by a large distance. Specifically, if something happens to one particle, it will automatically affect the other one, even though they are separated. To non-physicists, this might sound a bit like magic -- or pseudo-science at the very least -- and even Albert Einstein, whose research contributed to current quantum theory, described the concept as "spooky action at a distance."
But now, physicists have been able to produce entangled photons (or packets of light) in outer space, reports the Chicago Tribune, even without quite understanding how the phenomenon of quantum entanglement works. In a study published in the journal Science, physicist Jian-Wei Pan at the University of Science and Technology of China described how he and his team were able to produce these entangled photons on a satellite orbiting the Earth and then beam the particles to two different ground-based labs that were 750 miles apart, without losing the particles' mysterious linkage.
Specifically, on the satellite Micius, which launched last year, a high-energy laser was fired through a special kind of crystal, thereby generating entangled photon pairs. The photons were transmitted to two ground stations in China: one in the city of Delingha and one in the city of Lijiang, about 750 miles away from each other.
Quantum entanglement is exciting because it could one day be used for "quantum communication" or the means of communicating secure or confidential messages without cables, wireless signals or code. Because any interference with an entangled particle immediately affects its partner, these communications cannot be hacked. Entangled particles could also be used to build a "quantum internet," allowing for secure and lightspeed communication, which could have useful applications for hospitals, credit card companies and government agencies that are prone to cyber attacks.
The next step that Pan would like to investigate is sending quantum particles from the ground to the satellite and setting up a channel that would allow for the transmission of tens of thousands of entangled pairs per second. "Then the satellite can really be used for quantum communication," he said.