Quantum Radar Has Been Demonstrated For the First Time (technologyreview.com) 37
An anonymous reader quotes a report from MIT Technology Review: Shabir Barzanjeh at the Institute of Science and Technology Austria and a few colleagues have used entangled microwaves to create the world's first quantum radar. Their device, which can detect objects at a distance using only a few photons, raises the prospect of stealthy radar systems that emit little detectable electromagnetic radiation. The device is simple in essence. The researchers create pairs of entangled microwave photons using a superconducting device called a Josephson parametric converter. They beam the first photon, called the signal photon, toward the object of interest and listen for the reflection. In the meantime, they store the second photon, called the idler photon. When the reflection arrives, it interferes with this idler photon, creating a signature that reveals how far the signal photon has traveled. Voila -- quantum radar!
The researchers go on to compare their quantum radar with conventional systems operating with similarly low numbers of photons and say it significantly outperforms them, albeit only over relatively short distances. That's interesting work revealing the significant potential of quantum radar and a first application of microwave-based entanglement. But it also shows the potential application of quantum illumination more generally. A big advantage is the low levels of electromagnetic radiation required. Then there is the obvious application as a stealthy radar that is difficult for adversaries to detect over background noise. The researchers say it could be useful for short-range low-power radar for security applications in closed and populated environments. The researchers detail their findings in a paper on arXiv.org.
The researchers go on to compare their quantum radar with conventional systems operating with similarly low numbers of photons and say it significantly outperforms them, albeit only over relatively short distances. That's interesting work revealing the significant potential of quantum radar and a first application of microwave-based entanglement. But it also shows the potential application of quantum illumination more generally. A big advantage is the low levels of electromagnetic radiation required. Then there is the obvious application as a stealthy radar that is difficult for adversaries to detect over background noise. The researchers say it could be useful for short-range low-power radar for security applications in closed and populated environments. The researchers detail their findings in a paper on arXiv.org.
So cool! (Score:1)
Presumably cannot detect cats ... (Score:4, Funny)
as they will seem to be both there and not there at the same time.
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"useful for short-range low-power radar" (Score:2)
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Re: "useful for short-range low-power radar" (Score:1)
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Re: "useful for short-range low-power radar" (Score:3)
It also occurred to me that you're very likely an utter moron... but hey, we can't all not be stupid, right?? ;)
Re: "useful for short-range low-power radar" (Score:2)
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Would Nitrogen be cold enough? Perhaps they should use liquid Hydrogen and *really* get respect.
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Me: Your Honor, my speed at the time existed as a superposition of all speeds and therefore reasonable doubt exists.
Judge: The court hereby finds you guilty and not guilty. Fine is reduced by half. Pay at the court clerk window. Next!
(I'm sure this could use some improvement)
Heterodyne Lidar not QM (Score:1)
As described this is Heterodyne Lidar. Classical Heterodyne lidar is already known to extrapolate down to the single photon limit so this is not new at all. As decribed it is not a quantum lidar. There could be other attributes not described that make it more reliant on the entanglement but not in this blurb.
Re: Heterodyne Lidar not QM (Score:2)
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Not sure what you refer to. The idea that coherency can be exploited for sensitive detection is the basis of optical coherence tomography. It uses pseudo white light or boradband light to do the intereference to detect only the mutually coherent photons. but it's not QM per se
Fake Quantum. (Score:1)
But...but... quantum weirdness isn't real.
https://www.newscientist.com/a... [newscientist.com]
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The article is technical I have a summary ... (Score:5, Funny)
"Entangled quantum photon radar that is undetectable by the target, and will replace all existing radar technology."
It will produce a signature that will be listed in a blockchain syntheses, cataloging each discrete object examined, using bolt-on algos of AI, deep machine learning, with cohesive background scatterization and will include counting nose hairs for facial recognition and will be stored on an unconfigured AWS S3 bucket on the cloud.
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Bingo!
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This is why master criminals all have portable electric rotary nose hair trimmers.
Great for self-driving cars? (Score:2)
China already had it (Score:1)
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Yeah, keep telling yourself that.
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VHF band radar, as that can reliably detect a stealth fighter from hundreds of miles away.
For this to be true you have to turn up the sensitivity and leave the false positives out of the analysis.
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It is easy to detect stealth aircraft with a low frequency radar.
Problem: You don't get good information about where it is. "Possible stealth aircraft coming... somewhere... at some distance! Duck and cover?"
It can't be used to guide a missile.
Problem: The sensitivity required to detect stealth aircraft also detects insect swarms, individual birds, weather patterns. This combines in an unfortunate way with the problem above.
I understand and respect that they have to do PR, they have to build and install at
Um... (Score:3)
They beam the first photon, called the signal photon, toward the object of interest and listen for the reflection. In the meantime, they store the second photon, called the idler photon. When the reflection arrives, it interferes with this idler photon, creating a signature that reveals how far the signal photon has traveled. Voila -- quantum radar!
So they send a photon and wait for the reflected photon to return and measure the time interval? This is how *regular* radar works using radio waves (which are made up of photons) and round-trip signal time -- unless they're only sending one photon and crossing their fingers that its return path intersects with them and they detect it on its return.
Now, if what they meant to say is that the "idler" photon is interfered with *when* the "signal" photon gets reflected and they use the one-way time ...
Re:Um... (Score:5, Informative)
1) Radar range (as with all radio systems) is limited by noise from both the environment and the receiver components. You have to transmit enough power so that the reflected signal from the target is stronger than the noise. But, in a quantum radar the "noise quanta" (if you will) don't interfere with the stored photons and thus can be rejected. Therefore these is less noise and therefore you can transmit less power which means: (a) less cost (high power transmitters are expensive), (b) fewer rad haz safety problems, (c) less power consumption (assuming it isn't all now used for cryogenic cooling) and - for military systems - (d) low probability of intercept.
2) Resistance to jamming (again relevant only to military radars). Photons from a jammer will, like noise, not interfere with the stored photons and can be rejected thus making the jammer less effective.
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Thanks, I found the info you posted farther down in TFA -- which should have been higher up in that and actually in TFS as it's more pertinent to the topic and workings of this "quantum radar" than simply signal interval time.
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In the old radar, you send out an EM pulse, and measure its reflection. The problem being that there's lots of noise at precisely the frequency of your pulse which your equipment incorrectly interprets as a reflection. So your EM pulse has to be massive - big enough that any reflection is bigger than unrelated noise. A typical small boat radar using this method broadcasts at around 1500-5000
Dunno (Score:2)
"Then there is the obvious application as a stealthy radar that is difficult for adversaries to detect over background noise. "
So if it doesn't come back it means either there ain't nothing there or somebody intercepted it?
Doesn't that make it useless as a radar?
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If the photon does not come back, nothing is there (to whatever probabilities are usual for possible targets in question).
The question is how hard it is to be certain it is one of your photons that came back, over background instrument noise and possible jamming. So, if I understand correctly, this technique is intended to reduce false negatives (my photon came back but other photons confused my equipment so it was rejected) and reduce false positives (other photons were detected and the equipment incorrec
Military applications (Score:1)
If those researchers don't have a DoD contract yet, they will very, very soon.
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As the story explains, the expected utility is mostly in medical scanners that can use a low enough power level not to damage tissues.
The military isn't that interested in radar that requires superconductors that operate at millikelvin temperatures in order to detect objects a couple meters away.
Also maybe a security scanner to protect Congress or something. They're not going to put these in airports anytime soon. Scanning for contraband at close range: Yes. Scanning for military stuff at a distance? No. If