Sat, Jun 17, 2017 - Page 5 News List

China transmits entangled photons to Earth

GROUNDBREAKING FEAT:Chinese scientists managed to produce two photons that behave as if they were one entity and send them from a satellite to ground stations

AFP, WASHINGTON

Chinese scientists have pulled off a major feat with one of the subatomic world’s weirdest phenomena: photons that behave like twins and experience the same things simultaneously, even over great distances.

The space-based technique developed by the researchers and reported on Thursday in the journal Science holds potential for revolutionizing telecommunications and perhaps someday developing a hack-proof Internet.

The principle is called quantum entanglement, in which photons or neutrons are created in such a way that they are linked and behave as if they were one entity, even if they are physically separated.

In a groundbreaking experiment led by professor Pan Jianwei (潘建偉) of Hefei University in China, a laser on a satellite orbiting 482.8km above the Earth produced entangled photons. They were then transmitted to two different ground-based stations 1,207km apart, without breaking the link between the photons, the researchers said.

That distance is 10 times greater than the previous record for entanglement. The experiment also marked the first time entangled photons were generated in space.

Both stations are in the mountains of Tibet, at a height that reduced the amount of air the fragile photons had to traverse.

“It’s a huge, major achievement,” Canada-based University of Waterloo physicist Thomas Jennewein told Science. “They started with this bold idea and managed to do it.”

Entangled particles hold the promise of creating a communications system that can send secure messages without cables, signals or code: Any action on one of the twins is detected by the other, so the message sent along such a conduit cannot be hacked.

Those properties of quantum physics also hold the potential for superfast computers.

US and European teams are considering sending quantum-based equipment to the International Space Station.

One test would see whether changing gravitational fields affect entanglement.

Scientists would compare photons in the weaker gravitational environment of orbit with entangled partners sent to Earth, Vienna-based Austrian Academy of Sciences physicist Anton Zeilinger said.

“There are not many experiments which test links between gravity and quantum physics,” he told Science. “I’m personally convinced that the Internet of the future will be based on these quantum principles.”

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