# Quantum Radar?



## Foxbat (Mar 2, 2017)

An interesting article that may be of interest to those among us looking to improve the detection properties of their fictional space fleets
https://phys.org/news/2012-12-quantum-properties-jammer-proof-radar.html

Personally, I'd prefer something like Schrodinger's Radar (the target's there on your screen but when you fire at it, it's gone)


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## J Riff (Mar 2, 2017)

So, you can't measure it without it changes, unlike electrical signals, which can be read by harmonic resonance or whatnot. How long before someone does figure out a way to read/jam it? There's a SF story there right off the bat.


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## reiver33 (Mar 2, 2017)

If you can calculate the distortion caused by your measurement, then can't you build an appropriate bias into your 'stealth' modification? This assumes you have a copy of the enemy radar to experiment with, of course.


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## hitmouse (Mar 21, 2017)

The unjammability is a fundamental quantum property.


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## Ursa major (Mar 21, 2017)

Foxbat said:


> Personally, I'd prefer something like Schrodinger's Radar (the target's there on your screen but when you fire at it, it's gone)


The key part that makes such technology work has been patented and is restricted to use in the weapons of Imperial Stormtroopers....


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## tinkerdan (Mar 21, 2017)

I know I'm missing something vital here.
But: If measuring them changes them then how do they measure to verify since measuring will change them. How could they possibly get any sort of definitive low error rate from measuring them.


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## Foxbat (Mar 22, 2017)

tinkerdan said:


> I know I'm missing something vital here.
> But: If measuring them changes them then how do they measure to verify since measuring will change them. How could they possibly get any sort of definitive low error rate from measuring them.



Okay. I'm not a quantum physicist but here's how I understand it. 

To detect them, you have to somehow interact with them (which is the basis of the idea that observation changes things at this level). Interaction could take many forms but to give an example we can understand, it's very difficult to see something in the dark and easier to see in the light. But the use of light is effectively firing a stream of photons at the object (and the fact that you are doing this means you are interacting with and therefore changing the object). To take it further, the stream of photons may provide enough energy to change the trajectory of an object (and thus significantly change the results).

At this point (getting back to Quantum Radar) the photons are fired out in a known state. If they are reflected by an object, they will return in another known state (with statistically low rate of error). If there is interference in the process, they will return in a different state in a proportion that cannot be accounted for by statistical error...therefore...the observer can deduce that the data has been interefered with.

Of course, everything I have written may be complete nonsense.


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## tinkerdan (Mar 22, 2017)

I don't know it all seems pretty flaky to me since determining their state will effectively change them and it sounds like the determining the final result[what you expect to find]would be based on wishful thinking.


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## Parson (Mar 22, 2017)

Sounds like magic to me. [Parson winks a knowing eye.]


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## Foxbat (Mar 22, 2017)

I can't really disagree with you. I personally think that much of Quantum Physics is still wishful thinking (at least until we get definitive proof). 
An example....What is it that seems to glue together the smaller particles that make Protons and Neutrons? I know, we'll call it a Gluon


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## Ursa major (Mar 22, 2017)

The (so far undiscovered) particles that make the whole standard model work in a universe driven by quantum mechanics are simply not to be understood by the likes of us (simple people that we are)...



...which is why they are called stuckups....


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