A top Chinese military technology company shocked physicists around the world this week when it announced it had developed a new form of radar able to detect stealth planes 100km away.

The breakthrough relies on a ghostly phenomenon known as quantum entanglement, which Albert Einstein dubbed "spooky action at a distance".

China Electronics Technology Group Corporation (CETC), one of the "Top 10" military industry groups controlled directly by the central government, said on Sunday that the new radar system's entangled photons had detected targets 100km away in a recent field test.

That's five times the "potential range" of a laboratory prototype jointly developed by researchers from Canada, Germany, Britain and the United States last year.