[Swiftwater Gazette] quantum entanglement
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Mon Jun 19 06:51:28 EDT 2017
quantum entanglement http://www.news.com.au/technology/science/space/china-sets-new-record-for-quantum-entanglement-en-route-to-build-new-communication-network/news-story/e528da0cf68b2e63bbe093cab49ec507 China sets new record for quantum entanglement en route to buildnew communication network
CHINA has scored a victory against hackers and spooks as it surgesahead of other world powers in a new kind of space race. Chinese scientists have set a new distance record for beaming apair of entangled particles: photons of light that behave like twins andexperience the exact same things simultaneously, even though they’re separatedby great distances. The principle is called quantum entanglement and it’s one of thesubatomic world’s weirdest phenomena. And China has smashed the distance recordfor quantum entanglement. In a groundbreaking experiment led by Professor Jian-Wei Pan ofHefei University in China, a laser on a satellite orbiting 480 kilometres abovethe earth produced entangled photons. They were then transmitted to two different ground-based stations1200 kilometres apart, without breaking the link between the photons, theresearchers said in a report published in the journal Science.That distance achieved in the experiment is 10 times greater thanthe previous record for entanglement and is also the first time entangledphotons have been generated in space. “It’s a huge, major achievement,” Thomas Jennewein, physicist atthe University of Waterloo in Canada, told Science. “They started with thisbold idea and managed to do it.” China launched its first quantum satellite in August and if allgoes according to plan will send up plenty more to create a system ofcommunication which relies on entanglement. By launching a group of quantum-enabled satellites, China hopes tocreate a super secure network that uses an encryption technique based on theprinciples of a field known as quantum communication. “In physics we are trying, and we have demonstrated someencryption techniques that rely on the law of physics rather than themathematical complexity and we call this quantum key distribution,” professorPing Koy Lam from the ANU’s Department of Quantum Science told news.com.au lastyear, before China launched its first quantum satellite. “For that to work you need to send laser beams that carry certaininformation, quantum information, and then you need the senders and thereceivers to get together to find a protocol to secure the communication.” The reason it can’t be hacked is because the information carriedin the quantum state of a particle cannot be measured or cloned withoutdestroying the information itself. “We can show that this kind of quantum encryption works in a cityradius or at most between two nearby cities,” Prof Lam said. However China believes the atmosphere in space will allow thephotons to travel further without disruption because “in space there’s nothingto attenuate light.” In the latest experiment, both stations which received the photonswere in the mountains of Tibet, at a height that reduced the amount of air thefragile photons had to traverse. The successful characterization of quantum features under suchconditions is a precondition for a global quantum communication network usingsatellites that would link metropolitan area quantum networks on the ground The successful characterization of quantum features under suchconditions is a precondition for a global quantum communication network usingsatellites that would link metropolitan area quantum networks on the ground. China’s ongoing progress will no doubt be watched closely bysecurity agencies around the world.While the spectre of a communication network enabled via quantumsatellites is still a long way off, as China edges closer to the goal it hasled to predictions of a new space race. Quantum technology has been a major focus of China’s five-yeareconomic development plan, released in March 2016. While other space agencieshave been experimenting with the technology, none have seen the level offinancial support provided by Beijing. China has not disclosed how much money it has spent on Quantumresearch, but funding for basic research which includes quantum physics was$US101 billion in 2015 — an absolutely massive increase from the $US1.9 billionthe country spent in 2005. Scientists in the US, Canada, Europe and Japan are also rushing toexploit the power of particle physics to create secure communication systems,but China’s latest experiment puts the country well ahead of the pack. China launched the world's first quantum satellite on top of aLong March-2D rocket from the Jiuquan Satellite Launch Center in northwestChina.
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