View Full Version : Chinese Quantum Photon Radar
The end of stealth? New Chinese radar capable of detecting ?invisible? targets 100km away (http://www.cnbc.com/2016/09/21/the-end-of-stealth-new-chinese-radar-capable-of-detecting-invisible-targets-100km-away.html)
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.
America's Defence Advanced Research Projects Agency has reportedly funded similar research and military suppliers such as Lockheed Martin are also developing quantum radar systems for combat purposes, according to media reports, but the progress of those military projects remains unknown.
In a statement posted on its website on Sunday, CETC said China's first "single-photon quantum radar system" had "important military application values" because it used entangled photons to identify objects "invisible" to conventional radar systems. Nanjing University physicist Professor Ma Xiaosong, who has studied quantum radar, said he had "not seen anything like this in an open report". "The effective range reported by the international research community falls far below 100km," he said.
A military radar researcher at a university in northwestern China said the actual range of the new radar could be even greater than that announced by CETC. In a statement posted on its website on Sunday, CETC said China's first "single-photon quantum radar system" had "important military application values" because it used entangled photons to identify objects "invisible" to conventional radar systems.
Nanjing University physicist Professor Ma Xiaosong, who has studied quantum radar, said he had "not seen anything like this in an open report". "The effective range reported by the international research community falls far below 100km," he said.
A military radar researcher at a university in northwestern China said the actual range of the new radar could be even greater than that announced by CETC. "The figure in declassified documents is usually a tuned-down version of the real [performance]," he said. "The announcement has gone viral [in the radar research community]."
The scientists said they were shocked because, until recently, the idea of quantum radar had remained largely confined to science fiction. However, Ma, who was not involved with the CETC project, said serious technical challenges had long confined quantum radar technology to the laboratory........
The photons had to maintain certain conditions – known as quantum states – such as upward or downward spin to remain entangled. But Ma said the quantum states could be lost due to disturbances in the environment, a phenomenon known as "decoherence", which increased the risk of entanglement loss as the photons travelled through the air, thus limiting the effective range of quantum radar.
The CETC breakthrough benefited largely from the recent rapid development of single-photon detectors, which allowed researchers to capture returning photons with a high degree of efficiency. CETC said the quantum radar's advantage was not limited to the detection of stealth planes.
The field test had opened a "completely new area of research", it said, with potential for the development of highly mobile and sensitive radar systems able to survive the most challenging combat engagements. Quantum radar systems could be small and would be able to evade enemy countermeasures such anti-radar missiles because the ghostly quantum entanglement could not be traced, it said.
The company said it had worked with quantum scientists at the University of Science and Technology of China in Hefei, Anhui province, where many quantum technology breakthroughs have been achieved, including the world's longest quantum key distribution network for secured communication and the development of the world's first quantum satellite.
Lonewolf_50
22nd Sep 2016, 15:43
This means that HARM style missiles need to have a quantum receiver in their guidance module.
"Oh what a tangled web we weave"........
Well 70 years ago RAF pilots posted to the far east were warned of the dangers of oriental entanglements...
PDR
peter we
22nd Sep 2016, 19:53
Smells like Bulls*** to me.
Herod
22nd Sep 2016, 20:46
There was something in the paper the other day about a breakthrough in the "beam me up Scotty" field. From what I can gather, they managed to move a photon, a single photon mind you, across a city. As Peter says, it smells
tartare
22nd Sep 2016, 22:43
So let's look at this logically.
A Chinese defence company (Government controlled) succeeds in making an until now theoretical game-changing device work in the field.
And rather than keeping it up their sleeve and secret, the Chinese Government let them talk about it.
Somehow - I don't think so.
Lone - the countermeasure won't work anyway.
Quantum radar systems could be small and would be able to evade enemy countermeasures such anti-radar missiles because the ghostly quantum entanglement could not be traced...
Best countermeasure of all might just be a big ole nuklar cruise missile.
Let's see ya fancy smancy quantum radar deal with that!
So let's look at this logically.
A Chinese defence company (Government controlled) succeeds in making an until now theoretical game-changing device work in the field.
And rather than keeping it up their sleeve and secret, the Chinese Government let them talk about it.
Somehow - I don't think so.
Lone - the countermeasure won't work anyway.
Quantum radar systems could be small and would be able to evade enemy countermeasures such anti-radar missiles because the ghostly quantum entanglement could not be traced...
Best countermeasure of all might just be a big ole nuklar cruise missile.
Let's see ya fancy smancy quantum radar deal with that!
Everything was merely 'theoretical' once. Someone has to be first, and if this is a little preemptive, I'm sure it won't be too long before a deployable system exists somewhere. And why not the Chinese first? Doesn't seem too much of a stretch for a nation with the world's second largest R & D budget and ambition to match.
Isn't the entire principle of a systems deterrent value that your potential enemies know it exists?
As for the last point, well... Let's hope certain potential presidents and such have access to better diplomats and strategists than this (I hope) humour might suggest.
tartare
23rd Sep 2016, 00:24
If it exists - is it a deterrent?
And yes - I was joking... :rolleyes:
Edited to add - here a little more detail, and skepticism from a physicist (http://arstechnica.com/science/2013/01/you-cant-hide-from-quantum-radar/).
And if you really want to geek out - here's a research paper (http://scitation.aip.org/content/aip/journal/apl/101/24/10.1063/1.4770298). Interesting visual simulation of jamming detection - B2 or LRS-B type planform, versus a bird!
If it exists, it should certainly give any sane - minded commander pause for thought before sending in any of his billion dollar 'Golden Birds', or so one would hope. So yeah, I'd consider there to be a deterrent value - wouldn't you?
As for the article and paper you link to, well, they're both a few years old and seem to be authored by, shall we say, 'jobbing physicists'. You shouldn't infer disrespect in that statement, by the way - merely that a published paper is no guarantee of fundamental insight. The original article ORAC posted references 'spooky action at a distance', Einstein's glib dismissal of quantum entaglement which, of course, has since been proven correct by any number of observable experiments. Proof, surely, that even being one of the greatest intellects ever to have lived is no guarantee against being dead wrong.
And yes, your humour was understood. The worry is that for some, it may be interpreted as a valid, first move on the board.
A_Van
23rd Sep 2016, 14:02
IMHO, the prevailing context of such a "disclosure" was to threat "Uncle Sam" (maybe Japanese and Russians as well), to whatever extent it might work.
No doubt that though smart guys from MIT, Stanford, etc. plus engineers from Raytheon, LockMart, BAE and others can explain why it can't be implemented in real combat hardware of the current and next generations, it might trigger thoughts like "sounds damn lies, but who knows..." in some overconservative establishment members.
On the technical side, I think everything depends on investment monies. Recall that after Otto Hahn and Lise Meitner discovered nuclear fission of uranium back in winter 1938/1939, the first combat use of the results happened in 6+ years (i.e. quite soon). But the resources invested were really enormous...
IMHO, the prevailing context of such a "disclosure" was to threat "Uncle Sam" (maybe Japanese and Russians as well), to whatever extent it might work.
No doubt that though smart guys from MIT, Stanford, etc. plus engineers from Raytheon, LockMart, BAE and others can explain why it can't be implemented in real combat hardware of the current and next generations, it might trigger thoughts like "sounds damn lies, but who knows..." in some overconservative establishment members.
On the technical side, I think everything depends on investment monies. Recall that after Otto Hahn and Lise Meitner discovered nuclear fission of uranium back in winter 1938/1939, the first combat use of the results happened in 6+ years (i.e. quite soon). But the resources invested were really enormous...
It's also worth noting that Hahn & Meitner's (surely, one of the most underrated physicists ) discovery provided two routes to the creation of fission weapons. Upon validation of the theory, the U-235 'gun' weapon was guaranteed to work - the success of the Pu implosion weapon was far from certain and took (by far) the larger chunk of expenditure to bring to fruition.
Herod
23rd Sep 2016, 15:10
OK, I've found the article; the Times 21st Sep. Sorry, I don't know how to link to it. The Canadian experiment published in Nature Photonics, involved sending a message from a site on the outskirts of Calgary to the university of Calgary, by way of City Hall. Two photons were entangled at the university and one was sent to City Hall. At the same time a photon containing a message in the form of quantum information was sent from the suburbs to City Hall. At City Hall the two photons arrived and a measurement was taken transferring the information to the other photon. Through entanglement this change was instantaneously mirrored in the photon that stayed behind at the university. In the Canadian experiment there was a 25 percent success rate. In the Chinese one, the researchers from the University of Science and Technology of China were successful half the time.
http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2016.180.html
A long way from a "Death Ray"
Heathrow Harry
23rd Sep 2016, 15:19
History shows that there is a counter measure to every threat eventually
If the British could conjur up radar I'm reasonably sure that the Chinese will come up with anti-stealth measures in time
After all most modern stealth dates back to Ufimtsev's theoretical work in 1964 and Lockheeds development work on the F-117 40 years ago.
Herod, there are far, FAR easier routes to a 'death ray'. Laser and other DEW weapons technologies are maturing rapidly. It does, however, have pretty significant ramifications for comms tech further down the line (it's not worth guessing at timescales - predictions such as these are often woefully inaccurate - both pro and contra).
HH, indeed - all (!!) you need is to find the wherewithal to leverage the theory.
dumbled0re
24th Sep 2016, 07:58
The end of stealth? New Chinese radar capable of detecting 'invisible' targets 100km away | South China Morning Post (http://www.scmp.com/news/china/article/2021235/end-stealth-new-chinese-radar-capable-detecting-invisible-targets-100km) That article seems to be largely based on the following press release: http://www.cetc.com.cn/zgdzkj/_300931/_300939/445284/index.html (http://www.cetc.com.cn/zgdzkj/_300931/_300939/445284/index.html)
Note that the 100 km detection claim appears in the CETC press release, while the flamboyant references to Einstein and to stealth do not. Perhaps they were added by the SCMP journalist.
The end of stealth? New Chinese radar capable of detecting 'invisible' targets 100km away...
The breakthrough relies on a ghostly phenomenon known as quantum entanglement, which Albert Einstein dubbed "spooky action at a distance".
The article is so deep in hogwash that one hardly knows where to begin.
a) quantum mechanics does exhibit entanglement, and
b) even though Einstein ridiculed the idea of action at a distance, quantum mechanics actually does exhibit a certain type of nonlocality. However, those are not the same thing. Really not. Also, the nonlocality cannot be used to transmit information.
Meanwhile:
c) There is such a thing as "quantum illumination". It makes use of entanglement. It does not even attempt to exploit nonlocality, and any such attempt would fail anyway, because EPR-type nonlocality does not transmit information. Instead, quantum illumination relies on a beam that goes out and comes back, whereupon it is compared against a local reference (the "ancilla") that has been retained, locally. Meanwhile:
The end of stealth?
We can invoke Betteridge's law of headlines: Any headline that ends in a question mark can be answered "no". The stealth idea has been circling the drain for quite a while now, for reasons having nothing to do with quantum illumination.
d) As Peter G. rightly pointed out, all existing stealth aircraft show up on S-band and L-band radar, and on any longer wavelength.
e) To which one might add: Any stealth aircraft will show up on bistatic and multistatic radar. The aircraft scattering function has a null in the direct backscatter direction, directly back toward the transmitter. However, physics does not permit it to be null in every direction. There *will* be a pattern of nodes and antinodes.
If only they had an outpost in the South China Sea, it would make a great site for a multistatic radar installation. Oh, wait, maybe they already thought of that.......
f) Stealth aircraft also show up in the infrared.
This bag has been catless for many years. I reckon stealth technology is still effective against bush-league opponents, but I would be very surprised if anybody could fly into Chinese airspace without being picked up.
The article claims to be "news", but I'm not sure why.
g) The idea of quantum illumination goes back to 2008. Lockheed has a patent on "quantum radar" from 2008. There are entire textbooks on the topic of quantum radar.
h) If this were a real breakthrough, it would be highly classified. We would not be reading about on the CETG or SCMP web sites.
China's first "single-photon quantum radar system"
i) Mentioning single photons in this context is misleading at best. Quantum illumination systems use (or should use) coherent states, aka Glauber states. The Glauber-state basis is /incompatible/ with the photon-number basis. They are incompatible observables, in the Heisenberg sense. A Glauber state looks a whole lot more like a classical AC voltage than like a single photon.
j) Counting photons would be insane. The photon number operator is /quadratic/ in field strength. In second-quantized language, we can write it as (a†a). For a small signal, the photon number is small squared. Since the dawn of time, every radar ever built has instead measured the voltage, which is /linear/ in field strength, namely (a† + a).
k) There is no fundamental dividing line between quantum noise and classical thermal noise. They are two limiting cases of the same fundamental physics. The relevant scale-factor is Boltzmann's constant divided by Planck's constant, which comes out to 21 GHz per Kelvin. At the frequencies we are talking about (X-band and below) and at the temperatures we are talking about (300 kelvin or so), it's essentially all thermal. Calling it "quantum" radar is mostly marketing hype. A careful classical analysis of the apparatus would give essentially the same answer.
*) Et cetera. I could go on, but why bother? If you want to know about the interesting stuff going on in the radar world, this article is not a good place to start.
What kind and size of power source would be required for this kit and would it be feasible to fit into an aircraft?
Stable, large and no would be the full extent of my current 'best guesses' (sorry!).
Ask again in five - ten years.
Or I could just be plain wrong.
safetypee
24th Sep 2016, 14:34
Within the limits of my subscription to New Scientist, the principle appears to rely on the ability to create a pair (or more) of 'entangled' photons, which have identical properties, e.g. spin value, and maintain that state for sufficient time for one photon to be radiated and encounter an object, whilst retaining the other, yet maintaining the state of coherence.
If the radiated photon encounters an object in a way which changes the spin value, breaking the entanglement (coherence), then this change can be detected by a similar change in the retained photon. Einstein noted as being 'spooky at a distance'.
Reflection is not required, it's just the presence of an object which enables detection.
The physics of this is embedded in quantum theory, where most of this currently deifies explanation, but in practice 'things' work. Science has managed to entangle photons and hold them in a state of coherence for a reasonable time.
AFAIR coherence at distance has been demonstrated via optical fibre, such that the effect can be used to detect an eavesdropper, who breaks the coherence by looking at the data during transmission. The power required may be similar to laptop laser generation, which may depend on the transmission medium and range.
It's also reported that there have been demonstrations of free air coherence, again over reasonable distances - between islands in the Azores? Presumably the power requirements would increase, but without requiring reflection (or need to inflict damage) perhaps this is not excessive. The greater problem may be identifying a transmitting mechanism where the air or clouds do not cause de-coherence over longer ranges; perhaps a similar problem to the choice of IR frequency, an atmospheric window, water vapour, etc.
Where immediately my simple-mind approach retorts that a defensive 'cloak' could be a cloud of dust or steam; ... but then you detect the cloak ... Probably. [Like 'window' - chaff; 'window doesn't drop more window' so the front 'target' must be an aircraft - WIWOL].
The greatest problem for students of quantum physics is having to discard conventional scientific thought and accept that quantum effects are only probabilities.
Particularly in this instance where it is more probable that I have not understood the theory or practical application at all.
Please note this development is based at the same university which has just launched a quantum encryption distribution satellite, QUESS, (http://www.popsci.com/chinas-quantum-satellite-could-change-cryptography-forever)which has an initial aim of demonstrating entanglement at a range of 2,500km (https://en.wikipedia.org/wiki/Quantum_Experiments_at_Space_Scale).
This seems just a modest use of the same technology - where even the key is not needed, just evidence of interference when the photon collides with an object.
Safetypee, quantum mechanics IS consistent with conventional scientific thought and has been for the best part of a century. It is merely distinct from 'classical physics', with which the layman more closely identifies, as it describes (accurately) the macroscopic behaviour of larger scale structures. Whilst both fields are supported by hard, empirical evidence, the 'key' to a full understanding of how to reconcile this has yet to be found (the 'unified field theory'). An awful lot of the technology we use on a daily basis would not be possible without an understanding of the quantum world and its behaviours.
safetypee
24th Sep 2016, 16:20
JG :ok:
I’m just a probabilistic layman.
Does the empirical evidence reconcile with the claims being made?
Whilst I am merely a problematic hobbyist!
Nothing in the understanding of the mechanisms involved precludes it. Which is rather different to an extant, functioning fait accompli. Is it possible? Yes. Has it been done already? Perhaps. Will it be done? Certainly.
Time will tell, I suppose. Hopefully not in the form of a B -2 / B - 21 shoot - down!
Heathrow Harry
24th Sep 2016, 18:19
as has been pointed out turning the science into a working military system can cost zillions..... and the US has little interest in pursuing it as their potential enemies have little in the way of stealth forces. The Russians and the Chinese on the other hand have every incentive to invest big time
Chugalug2
25th Sep 2016, 13:54
I can't see this leading anywhere. If it did, how could the Klingon Cloaking Device be such a problem for Starfleet in the future? Nothing to worry about here, surely?
DumbledOre: Why bother? Well, because some of us may be interested - as you clearly are, having taken the trouble to register and post. Oddly, your post did not appear, for me, at least, until this morning, hence my late response. I'm genuinely intrigued - you seem knowledgeable on such matters, yet I also detect the faint whiff of vested interest - perhaps in some other, proprietary technology?
Chugalug: C'mon - surely you know that the whole 'cloaking issue' is a classical technological arms race, culminating in the development of 'gravimetric sensor nets'? :)
Trash 'n' Navs
25th Sep 2016, 17:48
The technology was talked about in open forum back in 2012
MIT technology review/quantum-imaging-technique-heralds-unjammable-aircraft-detection/ (https://www.technologyreview.com/s/508826/quantum-imaging-technique-heralds-unjammable-aircraft-detection/)
andytug
25th Sep 2016, 19:59
It does sound believable, but practical.....that's a whole other ball game. The gap between theory and practice is generally several years and an awful lot of failures.
Shades of the shooting down of the F117 over the former Yugoslavia(?) allegedly detected by the distortion of the local electric or magnetic field put up by power lines (iirc).
dead_pan
26th Sep 2016, 08:23
Who are we to complain if the Chinese want to waste their precious hard-earned on mad projects like this? Everyone needs a hobby I supposes....
Perhaps someone should tell them the Serbs knocked-up a cut-price system using TV transmissions....