China has taken a big step forward in its pursuit of a hack-proof communications network.
Chinese researchers say they have used a satellite in space to beam tiny particles over a record-breaking distance, according to an article in the latest issue of research journal Science.
The milestone highlights China's emergence as a major player in quantum technology, a field of science that aims to use subatomic particles in areas like secure communications and medical imaging.
China launched the $100 million satellite, known as Quantum Experiments at Space Scale, last August from the Jiuquan Satellite Launch Center in the Gobi Desert.
Less than a year after they launched the world’s only quantum communications satellite, Chinese researchers have for the first time ever sent entangled photons from space to ground stations on Earth.
“This is the first step towards worldwide secure quantum communications, and maybe even a quantum internet,” says Anton Zeilinger, an expert on quantum physics at the University of Vienna in Austria.
Before the launch, researchers placed a complicated system of lasers, mirrors, and a special crystal on board. When a specific laser shone on the crystal, it would create pairs of light particles known as entangled photons.
The crystal makes 6 million pairs of photons at a time, but on the ground, the two ground stations could only detect about one pair per second. “It’s a challenging task,” says Lu. “It’s like you have to clearly see a human hair from 300 meters away.”
This launch—and the actual experiment—was a long time coming. Jian-Wei Pan of the University of Science and Technology of China, the physicist who led the project, proposed the satellite experiment back in 2003.
The reason they could do it so quickly is that people at the highest level of the Chinese government prioritized the project, says Denis Simon of Duke Kunshan University, an expert on Chinese science policy.
Because the high-ups wanted it, the group didn’t have to go through the usual bureaucratic funding steps, he says.
The government is particularly interested in this technology because it wants quantum-secured communications in the national interest. “The Chinese government wants to communicate with their naval ships, " he says.
Source : New Scientist | Wired | CNN
