Submitted via IRC for Bytram
We're one step closer to atomic radio
Scientists at the National Institute for Standards and Technology in Gaithersburg, Maryland, have brought us one step closer to "atomic radio" by using an atom-based receiver to make a stereo recording of music streamed into the laboratory—namely, Queen's "Under Pressure." They described their work in a new paper in AIP Advances.
So-called "Rydberg atoms" are atoms that are in an especially excited state well above their ground (lowest-energy) state. This makes them extra-sensitive to passing electric fields, like the alternating fields of radio waves. All you need is a means of detecting those interactions to turn them into quantum sensors—like a laser. That means, in principle, that Rydberg atoms could receive and play back radio signals.
[...] The recordings aren't going to challenge the dominance of digital recording any time soon, since they are of much lower sound quality, more akin to an old vinyl record. That said, "My vision is to cut a CD in the lab—our studio—at some point and have the first CD recorded with Rydberg atoms," said Holloway—if only as a fun scientific curiosity. But one day, the researcher believes this type of atomic sensing could help improve secure communications. "Atom-based antennas might give us a better way of picking up audio data in the presence of noise, potentially even the very weak signals transmitted in deep space communications," he said.
DOI: AIP Advances, 2019. 10.1063/1.5099036 (About DOIs).
(Score: 2) by Rupert Pupnick on Sunday June 23 2019, @01:13PM (2 children)
Sounds like you’re thinking of something like a phased array, but the array elements need to have a spacing on the order of the wavelength of what you’re trying to receive to get any benefit. A hundred atom array might be about 1 nm across (depends on the atom) which is more than two orders of magnitude below the wavelength of visible light. An antenna is in some sense a spatial integator of EM power, so very small structures end up giving you very small signals.
So (assuming you’ve solved the problem of feedpoint design too) now you’ve got a really small signal that has to pass through a number of gain stages (with non zero noise figures) to give you something usable. If you started with a bigger signal from a properly sized antenna, you wouldn’t have this problem on this scale.
But, some might say, this is Quantum [tm]! Oh, so now you’ve quantized the signal into a finite number of levels. How many? It better be at least 2^16 if you want something as good as digital audio. Oh wait... what’s that about sounding like vinyl?
It’s BS.
(Score: 2) by Muad'Dave on Thursday June 27 2019, @03:59PM (1 child)
The actual radio transmission does not have to be analog - you can have a PWM or other digital signal that changes between as few as 2 quantum levels.
(Score: 2) by Rupert Pupnick on Thursday June 27 2019, @08:04PM
You’re certainly right about that, but TFA gave me the impression that the radio waves were analog, so that the atom had to be playing the role of A/D. Skimming through TFA again, I must concede that given its extremely high level of BS, your interpretation could be seen as equally valid.