
Scientists create quantum sensor that covers entire radio frequency spectrum - oedmarap
https://phys.org/news/2020-03-scientists-quantum-sensor-entire-radio.html
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peter_d_sherman
Related Paper:

Assessment of Rydberg Atoms for Wideband Electric Field Sensing

[https://arxiv.org/abs/1910.00646](https://arxiv.org/abs/1910.00646)

Mentally replace the word "Electric Field" with RF when you're reading it, and
you'll get it.

Also, according to the paper at least, in theory, laser interferometers can be
used to sense RF... which leads to the idea that perhaps the entire RF
spectrum, viewed as a single point in time snapshot, looks like an
interference pattern of all sorts of waves at all sorts of wavelengths...

From a series of those then, Fourier Transforms, ran over the whole dataset,
could be used to extract individual waves...

Also, there's some kind of vague relationship here with holograms too, because
holograms are in effect, interference patterns of two beams of laser light...

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montalbano
Any radio hams here have predictions for the use of this technology in amateur
radio?

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jdc
Not a ham, but this is at the "further research is needed" so I predict more
papers and grant money.

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m-p-3
Imagine having access to this instead of your regular software-defined radio.

Now I suppose this device is only able to passively listen to a signal but it
cannot transmit on its own, right?

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4gotunameagain
Technically you would have a software defined radio with this as an antenna,
and a wideband LNA. /pedantic

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bartwe
Got to appreciate the usage of Lego in that image.

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awelkie
This seems like it could be useful for UWB communications or a very precise
radar. Is it easy to generate an EM impulse with similar bandwidth? I guess
the difficulty is to do all signal processing in the optical domain, since
it's impractical to digitize all of that spectrum.

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fredsmith42
Would this be applicable to SETI?

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gus_massa
No. Any signal that reach here from other star system will be too faint, and
you need a huge antena to recollect enough power to detect the signal over the
noise. The discovery is very overhyped in the press article (as usual).

Also, the detector is small, but it need to be cooled to very low
temperatures, so the whole system will be not as small as the article
describe.

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mrfusion
A simple dish or antenna can collect the signal. Size it to your purpose. A
sensor is just the last step of what you do with that signal.

Think of putting your smart phone camera up to a telescope eyepiece.

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varjag
Antenna geometry restricts the effective frequency range.

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jameshart
Sounds like a key component we would need to make a real tricorder.

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daedalus2027
rydberg atoms? why they dont tellyou the exact element

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Tuna-Fish
The exact element does not actually matter here.

What matters is that the atoms in question have some of their electrons in
ridiculously highly excited orbitals. This dramatically changes how the system
works, and in fact if you have one highly excited electron and many tighly
bound core electrons, you can approximate the system by modeling it as
hydrogen, regardless of what element it actually is, due to how well the core
electrons shield the outer electron from the core.

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lioeters
> approximate the system by modeling it as hydrogen, regardless of what
> element it actually is

That's fascinating. I found corresponding statements in a Wikipedia article:

> Rydberg atoms have a number of peculiar properties including an exaggerated
> response to electric and magnetic fields, long decay periods and electron
> wavefunctions that approximate, under some conditions, classical orbits of
> electrons about the nuclei.

> The core electrons shield the outer electron from the electric field of the
> nucleus such that, from a distance, the electric potential looks identical
> to that experienced by the electron in a hydrogen atom.

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tomrod
Neat! Sounds energy intensive though.

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dmos62
It's noted that the sensors would be "very small". Doesn't size translate to
energy efficiency?

