An F-22 Raptor on full-afterburners, with contrails.pongky.n / iStock

Is stealth becoming obsolete?

The late Carl Sagan once said: "Extraordinary claims require extraordinary evidence."

And scientists in China are reportedly developing a new quantum radar technology that could detect stealth aircraft by creating a small electromagnetic storm, according to a recent study published in the Journal of Radars, a China-based peer-reviewed publication, reports the South China Morning Post.

However, this isn't the first time researchers from China have made big claims about a functional quantum radar, and many experts from other countries contest the very feasibility of such devices, suggesting that this could represent a technological bluff.

So take this with a grain of salt.

China makes big claims about a functional 'quantum radar'

Conventional radars have a fixed or rotating dish, but the quantum radar design more closely resembles a gun, and accelerates electrons to nearly the speed of light. Once they pass through a winding tube exposed to strong magnetic fields, the electrons could generate a vortex of microwaves that swirl forward like a horizontal tornado, according to the report. If successfully completed, the novel quantum radar system would outclass any radar system of the past, but that's still a big "if", according to Tsinghua University's Zhang Chao and his team, in the aerospace engineering school. But the potential benefits are worth the hard work, according to the team of scientists. The "better the stealth technology, the higher the gain" of the quantum radar system, they added, in the SCMP report.

However, the fundamental particles employed in this artificial electromagnetic storm would exhibit weird properties, added the researchers. In the study, each particle retained a spiraling momentum that didn't drop as time went on and distance increased. Einstein's work predicates that this isn't physically possible, but the researchers emphasized that quantum mechanics bypass the late physicist's theories, enabling the system to detect targets that conventional radar would never see. And it not only works from a great distance, but also during inclement weather.

'Quantum radar' may actually be a bluff from China

If the system really works, and is implemented in contested airspace, it could become a significant advantage. Even today, most planes can't disguise their signature from radar because they reflect electromagnetic waves. Stealth aircraft like the United States' F-22 Raptor or F-35 fighter jets, for example, absorb a large portion of the radar waves via a special coating material which, combined with minimal right angles in the external structure of the vehicle, can reduce a radar signal to an object the size of a baseball. Stealth technology like this has proved a distinct advantage against other nations' airpower that rely mainly on 20th-century jet fighters that lack stealth features.

However, recent years have seen military radar increase in sensitivity, possibly high enough to detect even stealth aircraft. But, in turn, novel metamaterials have further enhanced stealth capabilities, reducing aircraft visibility even more. And, if stealth technology continues to improve, some believe it will advance beyond the detection capabilities of any radar. This is why weapons engineers proposed quantum radar as a potential solution to the detection dilemma, more than a decade ago. Military scientists in China said they were already testing a quantum radar prototype in 2016, but this has been hotly contested by legitimate scientific authorities. A report published in Science Magazine last year argued that quantum radar may never be deployed for long-range uses like tracking stealth airplanes, since experiments have seen critical flaws — one of which suggested such devices only work near absolute zero — which obviously far below the temperature of China's skies. "I am convinced that when [China] announced their quantum radar it was not working," said Fabrice Boust, a radar specialist and physicist from France's aerospace agency, ONERA, in the 2020 Science Magazine report. "But they knew they would get a reaction." Well, if this is what China wants, it's working.