Chinese Quantum Photon Radar
Ecce Homo! Loquitur...
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Chinese Quantum Photon Radar
The end of stealth? New Chinese radar capable of detecting ?invisible? targets 100km away
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.
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.
This means that HARM style missiles need to have a quantum receiver in their guidance module.
"Mildly" Eccentric Stardriver
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
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!
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!
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!
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.
If it exists - is it a deterrent?
And yes - I was joking...
Edited to add - here a little more detail, and skepticism from a physicist.
And if you really want to geek out - here's a research paper. Interesting visual simulation of jamming detection - B2 or LRS-B type planform, versus a bird!
And yes - I was joking...
Edited to add - here a little more detail, and skepticism from a physicist.
And if you really want to geek out - here's a research paper. Interesting visual simulation of jamming detection - B2 or LRS-B type planform, versus a bird!
Last edited by tartare; 23rd Sep 2016 at 00:40.
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.
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.
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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...
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...
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...
"Mildly" Eccentric Stardriver
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/journa....2016.180.html
A long way from a "Death Ray"
http://www.nature.com/nphoton/journa....2016.180.html
A long way from a "Death Ray"
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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.
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.
HH, indeed - all (!!) you need is to find the wherewithal to leverage the theory.
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That article seems to be largely based on the following press release: 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 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:
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.
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.
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.
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.
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.
Ecce Homo! Loquitur...
Thread Starter
Please note this development is based at the same university which has just launched a quantum encryption distribution satellite, QUESS,which has an initial aim of demonstrating entanglement at a range of 2,500km.
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.
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.