IN A bid to build an entirely new kind of internet — completely secure and impervious to hackers — China has pulled off a major feat in particle physics.
Chinese scientists have set a new distance record for beaming a pair of entangled particles: photons of light that behave like twins and experience the exact same things simultaneously, even though they’re separated by great distances.
The principle is called quantum entanglement and it’s one of the subatomic world’s weirdest phenomena. And China has smashed the distance record for quantum entanglement.
In a groundbreaking experiment led by Professor Jian-Wei Pan of Hefei University in China, a laser on a satellite orbiting 480 kilometres above the earth produced entangled photons.
They were then transmitted to two different ground-based stations 1200 kilometres apart, without breaking the link between the photons, the researchers said in a report published in the journal Science.
That distance achieved in the experiment is 10 times greater than the previous record for entanglement and is also the first time entangled photons have been generated in space.
“It’s a huge, major achievement,” Thomas Jennewein, physicist at the University of Waterloo in Canada, told Science. “They started with this bold idea and managed to do it.”
China launched its first quantum satellite in August and if all goes according to plan will send up plenty more to create a system of communication which relies on entanglement.
A COMPLETELY NEW INTERNET
By launching a group of quantum-enabled satellites, China hopes to create a super secure network that uses an encryption technique based on the principles of a field known as quantum communication.
“In physics we are trying, and we have demonstrated some encryption techniques that rely on the law of physics rather than the mathematical complexity and we call this quantum key distribution,” professor Ping Koy Lam from the ANU’s Department of Quantum Science told news.com.au last year, before China launched its first quantum satellite.
“For that to work you need to send laser beams that carry certain information, quantum information, and then you need the senders and the receivers to get together to find a protocol to secure the communication.”
The reason it can’t be hacked is because the information carried in the quantum state of a particle cannot be measured or cloned without destroying the information itself.
“We can show that this kind of quantum encryption works in a city radius or at most between two nearby cities,” Prof Lam said.
However China believes the atmosphere in space will allow the photons to travel further without disruption because “in space there’s nothing to attenuate light.”
In the latest experiment, both stations which received the photons were in the mountains of Tibet, at a height that reduced the amount of air the fragile photons had to traverse.