Chinese defense giant China Electronics Technology Group Corporation displayed at a recent air show in the city of Zhuhai, what it claims to be a quantum radar that’s able to detect stealth aircraft. The company claims to have been working on the technology for years, and to have tested it for the first time in 2015.
Radar sends out a burst of radio electromagnetic energy, which bounces back when it encounters another object. Stealth aircraft try to get around this by becoming invisible to radar — either by using flat, angular shapes to reflect the signals away from radar equipment or by using materials which absorb the signals.
Quantum radar on the other hand uses two split streams of entangled photons. Only one of these beams is sent out, but due to a quirk of quantum physics both streams will display the same changes, despite being potentially miles apart. As a result, by looking at the stream which remains back home it’s possible to work out what has happened to the other beam.