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China Says It Has Developed a Quantum Radar That Can See Stealth Aircraft (digitaltrends.com)
An anonymous reader quotes a report from Digital Trends: At a recent air show in the city of Zhuhai, state-owned Chinese defense giant China Electronics Technology Group Corporation displayed what it claims to be a quantum radar that's able to detect even the stealthiest of 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. In principle, a quantum radar functions like a regular radar -- only that instead of sending out a single beam of electromagnetic energy, it 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. According to a brochure from the China Electronics Technology Group Corporation, the new quantum radar could "solve the traditional bottleneck [of] detection of low observable target detection, survival under electronic warfare conditions, [and] platform load limitations."
A beam seems like a really inefficient way of searching for something in 3D space. Also, if only one beam is sent out what happens to the second entangled beam? Photons aren't known for sitting still.
Awesome, so this disproves bell's theorem and thus re-writes the laws of WM as we currently understand them.
Or at least the simplified description of this does. perhaps the real process is different.
Bell's entanglement experiment results in a rather cool result that even though one can have spooky actions at a distance, you cannot use it to transmit information. That is you can if you compare results at each end see that there was a measurement induced correlation in the photons but you can't determine this from the statistical distribution of measurements at either end by themselves.
Thus you can't possibly see the aircraft in the local beam due to changes in the remote beam.
Some drink at the fountain of knowledge. Others just gargle.
If I'm reading this correctly, the exact same technology also enables faster-than-light communication.
Yep.
And if you can fling things around fast enough, faster-than-light communication enables future-to-past information transfer.
Bye, bye, grandma. (The grandfather paradox, female version, doesn't suffer from the "but it turns out grandpa was a cuckold" loophole.)
Fortunately for those of us who depend on causality for countinued existence, Bell's theorem says the radar doesn't really work.
(Though one that passes entangled photons past both sides of the plane, then measures their interference, might in principle detect the plane without exposing it to the photons. THAT one doesn't violate bell, lightspeed, or causality, but is pretty spooky.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
yes it is what Bell's theorem shows.
Here's how. Bell's theorem requires acting on the entangled pair in a way that will change the pair relationship. If you simply force one of the particles to a specific state then it breaks the entanglement and the other particle becomes independent. (thus no FTL info). And if you act on the entangled pair, then when you measure the local particle's state you also break the entanglement (thus no FTL).
here's a layman's description:
https://www.forbes.com/sites/c...
Some drink at the fountain of knowledge. Others just gargle.
PLA: We have not been able to figure out how to make stealth aircraft. We know our currently illegal expansion into the South China Sea will result in conflict in the next few years, with aircraft we cannot see. And our enemies will be able to see everything we have. So we have to figure out a way to make them think we're on equal footing, at least in terms of seeing aircraft, so they will delay stopping our imperial march through Southeast Asia.
Browsing at +1 - no ACs, I ignore their posts. So refreshing!
Your cause is a bit off.
If a country thinks it can win a potential war, it is better to hide their capability so enemies are unprepared.
If a country doesn't think it can win a potential war, it is better to advertise (claimed) newer capabilities so enemies are intimidated.
While the latter does mean the country will try to avoid a war, the former does not necessarily mean the country expects or wishes to go to war.
This posturing is kinda moot though since China and the U.S. will never go to war, since that would result in nuclear annihilation for both sides. The most they'll do is get into a proxy war with each country supporting opposing sides in someone else's war. Just like the U.S. and USSR did in Korea, Vietnam, Afghanistan, etc. (Actually i doubt China will even go that far, since unlike the USSR they do a huge amount of trade with the U.S. Which hopefully has taught them that economic competition is constructive, whereas military competition is destructive. They may pick opposite sides in a conflict, but it won't become a full-scale proxy war.)
As for China's artificial island, the U.S. doesn't need military power to defeat it. All it needs to do is help the Philippines and Vietnam build their own islands just outside Chinese waters. That'll put China in a position where if they insist artificial islands legally extend territorial waters, then the new Philippine and Vietnamese islands move the border of China's waters to halfway between those islands and China's mainland (basically cutting China's territorial waters in half). Then the U.S. can help those two countries build new islands just outside the new border for Chinese waters. Repeat until China's territorial waters only extend a few miles from shore. We could do this for a fraction of the cost of the F35.