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Scientists create quantum sensor that covers entire radio frequency spectrum (phys.org)
71 points by oedmarap on March 21, 2020 | hide | past | favorite | 20 comments


Related Paper:

Assessment of Rydberg Atoms for Wideband Electric Field Sensing

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...


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


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


Ham here. To my understanding, this only works with quantum computing. It may take a while before this trickles down to the amateur radio community.


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?


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


Got to appreciate the usage of Lego in that image.


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.


Would this be applicable to SETI?


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.


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.


Antenna geometry restricts the effective frequency range.


Where did "cooled to very low temperatures" come from? The Army article said it was done at room temperature: https://www.army.mil/article/212935


For radio astronomy purposes, the signal is so weak that thermal noise in the detector is always an issue.


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


rydberg atoms? why they dont tellyou the exact element


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.


> 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.


Neat! Sounds energy intensive though.


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




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