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Neutrinos travel straight through earth at the speed of light. Therefore, it seems that they could be great for intercontinental communication. Of course, I assume a lot still needs to be learned about detecting, producing and controlling neutrinos before they can be used for the practical purpose of communication.

My question: In principal, could neutrinos be manipulated similarly to radio waves for the purpose of communication? I mean, modulation, filtering, etc. ?

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  • $\begingroup$ Building a coherent wave state with fermions. Hmmm....tricky $\endgroup$ – twistor59 Sep 7 '13 at 7:34
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    $\begingroup$ Related: Microsecond trading with neutrinos . $\endgroup$ – dmckee --- ex-moderator kitten Sep 7 '13 at 11:42
  • $\begingroup$ @twistor59 Nawh. That's not the way to think of it. Think, instead of ultra-wide band. It is pulses in time space. Like WiFi, only without the selection of bands. $\endgroup$ – dmckee --- ex-moderator kitten Sep 7 '13 at 11:46
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    $\begingroup$ My answer to the following question physics.stackexchange.com/q/70132 seems relevant. $\endgroup$ – akhmeteli Sep 8 '13 at 10:35
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    $\begingroup$ Neutrinos do not travel at the speed of light through the earth, they are massive particles so are restricted to velocity less than c. $\endgroup$ – Triatticus Nov 24 '18 at 5:59
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We already know a lot about detecting, producing and controlling neutrinos.

Production in a controllable (switchable) way requires a particle accelerator. Enormous energy is not required but high current is. These are complex and expensive facilities. There are not something you can buy off-the-shelf.

Likewise detection requires large devices (tons to megatons of active volume, depending) simply because the neutrino--nucleon cross-section is insanely small at achievable energies. Again these are very complex and expensive devices (not the least because they are individually designed, constructed and tuned).

It also requires a team of experts to keep both the beam and the detector on-line.

The technical challenges are considerable, and the use cases for which the extra cost can be justified are almost certainly non-existent.

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  • $\begingroup$ When you say "enormous energy is not required", I assume you're referring the energy of the beam particles? I figure the actual total required energy (as in what your electric co. bill says) is quite a lot! $\endgroup$ – chase Mar 10 '14 at 12:13
  • $\begingroup$ @chase Yes, high beam energy. The cost of running the production facility would be considerable and would include a non-trivial power bill. $\endgroup$ – dmckee --- ex-moderator kitten Mar 10 '14 at 13:41
  • $\begingroup$ How about communication with nuclear submarines at depth? Not sure if the bandwidth would be any better than ELF transmitters... $\endgroup$ – Nick T May 25 '14 at 17:08
  • $\begingroup$ @NickT "detection requires large devices [...]" I'm sure the engineer is going to thank you for asking to put a 100 ton water Cerenkov tank in the middle of the boat he's designing. Worse, this system is directional: you need to point to within a degrees of the target. $\endgroup$ – dmckee --- ex-moderator kitten May 25 '14 at 17:12
  • $\begingroup$ Are the detectors (receivers) in the tons range the directional ones (in contrast with SNO or the like at megatons)? A 100 ton device doesn't seem unreasonable when the displacement of a sub is in the 8000-16000 ton range. You would need to be able to detect neutrinos at the very least over a 90° x few° swath, so given those constraints and that the transmitter would need to know roughly where you are...impractical, illogical, but not impossible? $\endgroup$ – Nick T May 25 '14 at 17:30
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Radio waves normally transmit information by amplitude or frequency modulation. This assumes there is a carrier wave that can be modulated, and as twistor59 says in his comment, creating a carrier wave using neutrinos would be very difficult.

However many radio and TV stations are already streamed digitally, and in principle neutrinos could be used for this. I say in principle because, as you say in your question, neutrinos interact too weakly for this to be possible in the near future.

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  • $\begingroup$ The right model is more like ultra-wideband radio (pulses in time-space) than radio (variations in wave parameters with time). You simple turn the beam on and off on a time scale long enough for the detector to unambiguously determine which is which. Or allow some ambiguity and use a ECC to optimize the rate. An accelerator source can do this at nanosecond time-scales, though right now no detector system can respond that fast. $\endgroup$ – dmckee --- ex-moderator kitten Mar 10 '14 at 15:03
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In the fall of 2000, Dr. Joseph Weber of Weber bar gravity wave detector fame delivered a presentation before an international group of satellite engineers in the Reiger auditorium of the former Comsat laboratories in Clarksburg, MD.

He told us that he had developed an ultra-sensitive neutrino detector that was basically a large (palm sized) crystal of pure silicon set inside of a NMR (nuclear magnetic resonance) imaging device. He said that the effect of the nearly perfect silicon lattice was to make the cross section susceptible to neutrino detection larger, and that if a neutrino should strike a single atom in the silicon crystal lattice, they would all vibrate in a manner that he could detect with the NMR setup. So, according to Joe, it was relatively easy for him to detect neutrinos, and all we needed to do was to come up with a way to modulate a beam of neutrinos, and satellite telecommunications would become obsolete overnight.

I told a neutrino physicist (a former assistant to Nobel Laureate Ray Davis) about Joe's ideas about neutrino detection. Jack told me that the idea was not original with Joe, and that it did not work. Furthermore, Joe's Weber bars never detected a single confirmed instance of gravity wave either. Neither has LIGO as yet, so there's no shame or blame here.

Be that as it may, the various methods for producing a beam of unmodulated neutrinos, even from facilities like CERN's LHC are pretty much ad hoc and slap dash (literally), from the descriptions I have read. Communication is really not their specialty nor the reason for constructing their facility. Neutrino communication on the order that Joe Weber envisioned will likely remain something that is in the realm of science fiction until we learn more about how better to produce and detect them.

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  • $\begingroup$ This is roughly the manner in which solid-state direct dark matter detectors work, and provides sensitivity to low-energy, neutral-current scattering. There are more such interaction than ones that we can see with conventional detectors, but there is also a lot more background. You can reduce the product (mass of the detector required) times (beam intensity at the detector)) by the same ratio that you increase the total detectable cross-section. $\endgroup$ – dmckee --- ex-moderator kitten Mar 10 '14 at 14:59

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