China Says It Has Developed a Quantum Radar That Can See Stealth Aircraft (digitaltrends.com) 211
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."
Riiiight (Score:4, Informative)
They wouldn't admit this to the world if they really had it, and it really worked. Sounds like another Chinese hack to me.
Bonus: it disproved Bell's theorem! (Score:5, Interesting)
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.
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Actually you've got that exactly backwards.
Bell's theorem:
No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics.
with superdeteminism being the notable exception.
From Wikipedia https://en.wikipedia.org/wiki/... [wikipedia.org]
If a measurement setting in one location instantaneously modifies the probability distribution that applies at a distant location, then local hidden variables are ruled out.
Basically, Bell's Theorem states that quantum entanglement MUST transmit quantum information faster than light - without that, no theory can describe all observed quantum phenomena (unless the universe is absolutely deterministic with no possibility of free will - a proposition which is pointless to discuss further since the outcome of such a discussion
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First let's not argue what or what not is in Bell's theorem given that we violently agree that you can't transmit information faster than the speed of light.
THe work surrounding bell's theorem seems to establish two things
1. state changes can be transmitted faster than the speed of light (as we both agree)
2. That the nature of the state changes cannot transmit information faster than the speed of light (I aver and I think you agree).
So however you want to state it, information can't be tra
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Actually I remain unconvinced of the impossibility of transmitting information faster than light - all the proofs I've seen all rely on assumptions which seem overly conservative to me. Not that I'm expert enough to fully understand the proofs, but I'll trust the experts when they say "these are the assumptions this proof depends on"
Re:Bonus: it disproved Bell's theorem! (Score:4, Insightful)
Harnessing that fact to transmit classical information faster than light is a completely separate question. But nobody is claiming that is happening here.
That is exactly what the summary is claiming is happening:
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.
That is precisely what you cannot do: examining the photons you have doesn't tell you any information about what has happened to the photons you sent out, the only "information" it gives you is (basically) the what the state the photons you sent out will be if they haven't interacted with anything (you don't, however, know if they have interacted with something or not). Since the point of radar is to interact with whatever you're looking for, that makes it rather pointless.
Note that a "quantum radar" could maybe improve on classical radars by comparing reflected photons to give you more information about what exactly reflected them, but it's still only useful if you get some of the photons you send out back. Even then I doubt you could actually make such a system (I'm not entirely sure it's physically or even theoretically possible). I am sure, however, the Chinese don't have such a system: they would never publicly disclose it if they did. The only reason to brag about it's existence is to either convince other countries to waste time trying to replicate it, or to convince them their stealth fighters will be useless against the Chinese. Either way, it's a purely psychological move.
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The article's description is flat our wrong. The idea behind quantum radar is that the photons used to generate the microwave signal are first entangled with photons that are kept inside the system, and then when the system receives returning microwaves, it's able to compare them to the entangled photons and filter out background noise and enemy jamming signals. The filtering out of background noise is what in theory would allow quantum radar a greater chance to detect stealth aircraft, which normally rel
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More likely, given the scientific capabilities of the U.S., Russia, and several others, the company is merely groveling befor their alleged government. Think Roger Rabbit, "Pllbbbbblleeeese give us some money to cover our mismanagement...see, we have Quantum Radar!!"
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No. The article says that information is recovered. It does not say it happens faster than light. In Earth distances, light is pretty fast, so you can IN THEORY have "real-time" radar that involves quantum entanglement. This might be vaporware, but at least the summary isn't making impossible claims.
Dear Richard Feynman, please advise (Score:2)
I've never entirely agreed with that formulation. Any machine you can build that verifies this theory does so using only information that travels at the speed of light.
So your other explanation is that all the information flows in this experiment, from the entangled particle, through the physical apparatus remain entangled until the final green light goes on (Bell's theorem verified).
All it takes is
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Even if I'm wrong, I'm 50% correct
Fucking millennials.
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What I expect from free will is simple, if difficult to observe conclusively: that I could act in a manner other than I do. That my changing thoughts, aspirations, and ideals can influence my future actions. Or alternately, at the most simple, that my actions could not be perfectly predicted beforehand. Superdeterminism denies that - as every action I will ever make was known with absolute certainty from the first moment of the universe's existence. As such it completely denies the value of consciousness
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>In this case whether or not the discussion occurs is also pre-determined along with the outcome.
Quite - so, *if* I have a choice, I choose not to have the conversation, since my choice disproves the premise. And if I don't have a choice, it doesn't matter.
Schrodinger's radar (Score:5, Funny)
It detects the plane if you don't look at the radar screen
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The opposing army should just bring a bunch of really gigantic boxes into the field with them, then refuse to look in them.
The losses of the Chinese Air Force will be astounding!
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Re:Bonus: it disproved Bell's theorem! (Score:4, Interesting)
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... [forbes.com]
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But regardless of arguing over what is or is not rolled up in Bell's theorem at least we both agree on the general principle that there's no FTL.
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In particular, the quantum radar does not claim any FTL nonsense. A beam is sent out, and reflected from the target. A very weak reflection, in case of a stealth plane. The quantum radar is not faster, it is merely able to see that extremely weak reflection because it is not hampered by background noise (natural microwave noise or electronic warfare jammers).
Read the wikipedia article on quantum radar. The principle is so old it has a wikipedia page - the only "new" here is that China claims they have a wor
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I was going to jump in with something about violating causality, then I thought, better wait for somebody who actually knows what they're talking about.
Maybe they will follow up with an improved perpetual motion machine or a breakthrough in cold fusion.
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A breakthrough in basic physics would also be helpful because the energy cost of producing a muon is 6 GeV while each D-T fusion yields .0176 GeV of heat and is captured by a helium nucleus on average once per 1-200 reactions. Generating electricity costs another factor of 2.5, so the energy gap is nearly an order of magnitude.
Store muons? I think that's a fanciful embellishment of your own, and thank you for explaining the length of a microsecond.
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China is smart and they have put their quantum stealth radar into a black box, as a result they are not sure if it exists or not.
Re: Riiiight (Score:2, Insightful)
Stealth planes were operational before announcement
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If this worked, it would allow faster than light communication. Send one half of an entangled pair of beams to someone (traveling at the speed of light, but that’s just the setup, not the actual communication), then the recipient disturbs the beam (or not), and the other party instantaneously notices. Nope, not possible.
Mod parent up. Thread over.
Re: Riiiight (Score:5, Informative)
That's not how entanglement works. Maybe they are using some other kind of quantum effect. But entanglement actually does work instantaneously, faster than light. It just works in such a way that you cannot use it for communication. If you measure the particles at both ends, you will get the same result instantaneously (while you can prove that the decoherence occurred at that exact moment, not earlier, and therefore some kind of "information" must have traveled FTL) but you have no control over that result, and you cannot tell whether or not the other party made a measurement. So you cannot use it to send a message.
Re:Riiiight (Score:5, Insightful)
If a country believes that war is likely or inevitable, it is better to hide their capability so enemies are unprepared.
If a country is primarily interested in deterring war, it is better to advertise new capabilities so enemies are intimidated.
Historically, America has tended to follow the first strategy, and keeps new developments secret.
Most of America's adversaries have tended to follow the second strategy. During the Cold War, Russia often tried to look stronger than they really were. Today, China does the same.
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Re:Riiiight (Score:4, Interesting)
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.
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Hmm (Score:5, Interesting)
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.
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Whatever you do, DON'T CROSS THE BEAMS!!! That would be Bad(TM).
Thank god you're nothing but one of those fake Ghostbusters you see on TV. You'd probably cross the streams and kill us all if you ever tried to man up and bust ghosts for real.
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It's not a steady-state beam, it's a highly directional pulse.
So... You need to already know where the plane is in order to use it? Seems a little paradoxical for a radar...
Re:Hmm (Score:4, Informative)
Not at all. In modern world, warfare generally uses two different radar types - search radar which you can see spinning around in at 360 degrees and fire control radar that uses a directional pulse/beam. Problem with stealth is that it can be tracked by radar with low accuracy, i.e. you can get the general direction where aircraft is on your search radar, but you can't get a high accuracy track needed for fire control radar to be effective. So detection of stealth aircraft isn't a problem for modern radar systems. Tracking them accurately is.
That means that if you can develop a fire control radar that can produce a track accurate enough for a missile to be effective, stealth becomes effectively reduced or even nullified for purposes of anti-air warfare.
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Well it is necessary for out in actual space but in atmosphere, it is largely a waste of time. Far more efficient to create atmosphere mapping radar, which maps the entire atmosphere with in it's range, basically what the air is doing where and when. So detect clouds, flocks of birds, aircraft exhaust and of course the atmospheric hole aircraft create and so not only detect planes for targeting but also weather radar, more needs to be done in efficiency of military spending, military use only should be an a
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Most radars are beams (Score:2)
think of the canonical radar screen with the rotating antenna. it's a beam. Sure you can now do phased arrays but beams were the original incarnation
Beams (Score:2)
The second beam isn't aimed at anything, but can be measured, to determine what happens to the first beam. That's what quantum entanglement is, in a very crude sense.
Err, entanglement breaking? (Score:3)
DWave (Score:4, Funny)
Fusion-powered flying cars! (Score:2)
Fusion-powered flying cars, please.
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FTFY.
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"The future's bright, the future's homogenized.
( And fusion-powered. )"
And 3-D printed!!
The important question is... does of any of this mean that "I gotta wear shades...."
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Only if you’re getting good grades.
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The important question is... does of any of this mean that "I gotta wear shades...."
If there is a nuke in your future, sure.
Does Fallout 76 count....
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How can people here actually be this bad at detecting snark?
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I'm still waiting for my flying car and jet pack as promised by Popular Science.
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If he's going to pull that off it'll have to be anything but straight - in fact it will have to bend in directions not currently known to man, as all the (hypothetical) ways we know of to build a tunnel between planets would cause both planets to implode shortly thereafter.
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How about a sneak peak of this device then? (Score:2, Troll)
Sounds like they have been watching too much Sci-Fi or they just wanted to call it Quantum Radar when its just really an narrow band radar.
What's next, they are working on a Reverse Quantum Phase Radar Interfe
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If someone jams their quantum radar, they just reverse the polarity.
Lies (Score:2)
That isn't how quantum entanglement works. China Electronics Technology Group Corporation is betting that readers are stupid or ignorant or both. That's a relatively safe bet, too.
The radar might still work, since there are other ways to design good radar.
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It seems unlikely that you'd demonstrate your super stealth breaking radar at an air show.
Re: Lies (Score:2)
FTL Communications? (Score:2)
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its all gone plaid
Re:FTL Communications? (Score:5, Interesting)
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.)
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>Bell's theorem says the radar doesn't really work.
How do you figure? Bells theorem rules out local hidden variables, which implies that faster-than-light quantum information transfer MUST be included in any quantum theory capable of describing observed phenomena. (barring superdeterminism)
Another claim (Score:5, Insightful)
They had a similar story last year, and the year before. It's not true. If it was, the last thing they would do is tell everyone that they can see stealth plans (or at least how they did it so it could be duplicated/nullified.) But it's not true. It's designed to impress someone, I'm not sure who.
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Re: Another claim (Score:2)
It's designed to impress someone
It's propaganda meant to intimidate but they certainly get points for entertainment.
It's not to impress (Score:2)
It's a classic cold war technique. The goal is to make your opponent drive themselves into bankruptcy trying to match you. We used it on the Russians and it pretty much wrecked them.
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I hardly think the U.S. military is likely to fall for this. However, given the scientific grasp of the Administration, maybe you are right.
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Duffman (Score:2)
Duffman/China, says a lot of things!
Here it is (Score:3)
First photos revealed. [ancient-origins.net]
This set off my ... (Score:2)
... quantum bullshit detector.
They are mixing the science of quantum entanglement with fucking ballistic particles.
And "2015?" Goddam stealth anything bigger than mesoscopic size is Classical.
Why the simple hell didn't they mention blockchain?
Re: This set off my ... (Score:2)
Why the simple hell didn't they mention blockchain?
Why would they reveal their secret ingredient??
TRANSLATION (Score:5, Interesting)
Re: TRANSLATION (Score:2)
PLA: We have not been able to figure out how to make stealth aircraft.
Pfft, they can't even figure out how to manufacture a modern jet engine.
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The PLA has some pretty good stealth aircraft actually.
Bad description of quantum radar (Score:5, Informative)
The article gives a pretty poor, if not outright wrong, explanation of what quantum radar is supposed to be. The idea behind quantum radar is that the microwave signal sent out by the radar system is first generated by one half of an entangled photon beam, and this is done in a way that maintains the quantum state as the photon beam is converted into a microwave signal. When the microwave signal returns after bouncing off a target object, the system is then able to use a comparison to the other half of the entangled photon beam in order to filter out any background noise. This would prevent an enemy from being able to using signal jamming to interfere with your radar. It would also make it easier to detect a stealth aircraft because no stealth aircraft is 100% invisible to radar, and quantum radar would, in theory, be able to pick out very small radar returns, that would normally be lost in the background radiation.
No need to RTFA (Score:2)
The usage of the words "Chinese" and "developed" in the same sentence is sufficiently descriptive of the utility of the linked resource. Useless!
Re: No need to RTFA (Score:2)
Here's a thought (Score:5, Insightful)
If China is claiming the technology to " see " stealth aircraft is now a reality, why are they still spending big $$$$ on building stealth aircraft ?
China is fixated on image. They took that whole " fake it till you make it " saying to heart and desperately wants the entire planet to believe they are the most amazing, powerful and capable country in history.
It should be noted the term " Paper Tiger " originated in China. They should be all too familiar with what it means since they are basically the very definition of the word.
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Does it run on fairy dust and unicorn farts? (Score:2)
Re: Does it run on fairy dust and unicorn farts? (Score:2)
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Bad physics = bullshit (Score:5, Informative)
There are three parts to their claim and they're all pseudo-babble junk:
1. A "stream of photons" can detect a stealth aircraft from some useful distance
2. Photons can be entangled on the fly (in real "stream" speed)
3. The entangled stream at home can be analyzed on the fly (same speed)
1.
Can photons be entangled? Sure. Can they be entangled at the speed of light such that a "stream of photons" (going out sequentially at the speed of light) are all entangled... possibly, but not with current technology and not with 2015 technology.
Think of it this way... physicists spend days setting up a quantum entanglement experiment where they entangle ONE or even TWO and sometimes FOUR (http://iopscience.iop.org/article/10.1088/1402-4896/aa736d) photons. To entangle enough to create a "stream of photons" and then sweep the skies two or three dimensionally for stealth aircraft is orders of magnitude beyond current tech.
2. It takes experiments ages (in photon time) to get photons entangled. Our primitive tools (electronics) uses electrons in a wire, which are slower than photons in air or in vacuum. Our tools simply cannot hammer these fast-moving nails fast enough... so what we do is fire a crap-ton of nails at our slow moving hammer and hope we can hit one into the other into the detector.
3. See #2. We don't have the speed with our slow-moving tools to analyze a photon stream.
I'm calling physics bullshit.
Ehud
Adding a sci-fi word? (Score:2)
"Quantum Radar"? China, you can't just add sci-fi word to another word and hope it means something!
True Story (Score:5, Funny)
China both has and does not have a quantum radar.
They won't know until they open the box.
And yet... (Score:2)
They've developed quantum radar that can see invisible airplanes and yet they still can't drive...
*Note : Extreme use of sarcasm*
That's nothing, China. (Score:5, Funny)
How 'bout them aliens? (Score:2)
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Re: BS meter bending the needle on the peg (Score:2)
This "Schrodinger's Cat Scan" radar doesn't seem credible to me.
What gave it away? (/sarc)
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And contrariwise, just because you DO understand something, doesn't mean that it does actually exist.
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I would suppose they look at the beam that reflected back.... but of in that case you don't need the other entangled beam for anything, HAH.
sounds like a load of B.S. to me.
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Re: Zach Patterson / ZIP = "better programmer" - n (Score:2)
He lives with his mother, so he has her at least. I suspect it's a Norman Bates type relationship.
Re: The really important question is.... (Score:2)
Gene Roddenberry