# Alternatives to electromagnetism for communication?

It seems, from my (weak) understanding of the standard model that the only field suitable for long range communication is the one we actually use, electromagnetism. (Gravity waves could be used as well I suppose, but gravity is too weak to be practical use.)

Questions:

1. Is this correct? It seems so, as you need a boson (to be able to produce 'intense' signals) and all the others are either unstable or strongly interacting (e.g. gluon)

2. Why is it like that? Is there some underlying fundamental reason that there are no other 'useful' bosons?

3. Does 'beyond the standard model' physics provide any insight? Any potential alternatives? (Graviphoton?)

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## 3 Answers

Yes, this is correct. The reason for Photons being our only means of long-range communication lies in the fact that at very low energies (where we live today) the unbroken subgroup of the standard model is $$SU(3)_c \times U(1)_\mathrm{em}$$ The $SU(3)$ color part is not useful, as it is confining at low energies. The $U(1)$ electromagnetic part gives rise to a chargeless, massless boson that interacts with everyday matter, so it is perfect for that purpose.

You are correct in assuming that gravitons would in principle work as well, but their coupling to matter is just too weak for any practical applications. Same goes for Graviphotons.

Physics beyond the Standard Model always has to have the Standard Model as a low-energy limit. Therefore, even if new bosons arise, they either have to have tiny couplings (e.g. axions) or large masses (e.g. GUT gauge bosons) in order to explain why we have not seen them yet. If by now we have not had a chance to see the damn thing, how would we use it to communicate?

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it is not as correct as stated, it is a (plausible?) speculation –  Nikos M. May 29 '14 at 22:50
@NikosM. I would like to know where I went wrong, so I can correct the answer and learn more myself. Can you provide some reference? –  Neuneck May 30 '14 at 8:06
gravitons are a speculative entity (in the fashion of a boson with spin=2) of some GUT-type theories, as also of course are some super-symmetric partners of (experimentally found) elementary particles, does this answer your question? –  Nikos M. May 30 '14 at 8:11
it is not only known if gravitons exist (or exist in that format) but also not known if communication (as with photons) can be achieved even in principle, i think what i just stated is correct, if it is not so, feel (very) free to correct me –  Nikos M. May 30 '14 at 8:14
@NikosM. Agreed, gravitons are hypothetical, but they are independent of the GUT framework. Even GR predicts gravitational waves which could in principle be used for communication - as with photons you have a wave-like phenomenon. The meaningful difference would not be that they are tensor waves (this just means that a linear antenna would not work - interferometers could in principle work, though), but rather that they are non-linearly coupled. Still, not even binary pulsars can create gravit. waves strong enough to challenge the linear approximation, so no man-made technology will, either. –  Neuneck May 30 '14 at 9:21

I believe long-range communication using weak interaction ((anti)neutrinos) is also possible, at least, in principle (see my answer at Are Electromagnetic Waves The Only Means of Transmitting Information? ). I don't quite see why communication using fermions is not possible.

EDIT(05/24/2014): It looks like neutron beams can also be used for long-distance communications, at least if guiding structures are used (http://www.manep-nccr.ch/en/technological-challenges/neutrons.html )

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I discounted fermions in my question, but found this article about using neutrinos: physicsworld.com/cws/article/news/2012/mar/19/… –  DrEntropy May 24 '14 at 16:56
@DrEntropy: I guess the source you quote is based on the work quoted in my answer to the other question. –  akhmeteli May 24 '14 at 17:02

Another field used for communication is the pressure - velocity field of material media. See: http://en.wikipedia.org/wiki/Acoustic_theory. For example, long range communication through solid and liquid media are exercised by elephants and whales respectively.

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you mean... "sound"? –  Dmitry Brant May 25 '14 at 16:22