Could you use Muons as electricity (or rather mutricity)?

Question

Muons and electrons are both leptons that carry charge, so could you build a circuit that uses muons instead of electrons? Do substances like copper that conduct electrons also conduct muons?

Answer 1

You can use any charged particle to carry an electric current. We like to say that current is carried by electrons because, in metallic conductors, there is a gas of conduction electrons who are much more mobile than the positive ions which make up the crystal lattice. But in nonmetallic conductors, the mobile charge carriers may have either charge. In pure water (which is not a great conductor), the $\rm H^+$ ions are more mobile than the $\rm OH^-$ ions. In salt water there are many options, because chemists use "salt" for a whole class of compounds, not just for table salt (halite, sodium chloride). Some comments below mention quasiparticles as charge carriers, even though that's kind of a reach from your question.

It would be hard to build a circuit using muons because they are unstable: muons decay into electrons (and neutrinos) in microseconds. The "drift velocities" of mobile charges in a circuit are very slow. However, if you have a muon particle beam in an accelerator or a storage ring, the current carried by the beam is a correct way to describe its intensity.

Answer 2

For the purposes of this answer, I'll be ignoring the fact that muons have a very short lifetime, and instead talking about how a fantasy version of a muon, one that is identical in every way to real-world muons except that it doesn't decay, would behave. Real muons' short lifetime would obviously prevent any useful uses of this hypothetical "muicity".

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Muons are unlikely to be conducted through material that also has electrons in it; they would immediately fall into very low-energy valence shells and be unavailable for conduction.

Because muons are not electrons, they are unaffected by the presence of electrons (other than by their charge, naturally), and would simply begin to fill their own totally separate set of atomic orbitals.¹ Due to the muon's high mass, these would be much smaller than the electron orbitals, so even if you were to have an equal number of muons and electrons, the muons would be huddled too close to the nucleus to make the jump to adjacent nuclei, so any conduction would be done entirely by electrons.

If, instead, you were to entirely replace all electrons by muons, then yes, the outermost muons in metals would be used in conduction. However, whether there are any metals with all muons is another question; the electron structure is what defines the behaviour of an element, so replacing electrons with muons like this will completely change them, essentially creating a new set of elements. I couldn't comment on the properties of these "fully muonic elements" (but hey, fodder for sci-fi writers out there who need to make a magic unobtainium, perhaps?).

Now, if you were to inject the muons into a vacuum, they would conduct electricity through that vacuum just the same as how electrons can conduct through a vacuum in a vacuum tube. But the thermionic effect isn't going to cut it here (you can only "boil off" the most loosely-bound electrons, and the higher-mass muons will be more tightly bound); you'd need some other way of getting the muons into the vacuum.

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¹The Pauli exclusion principle, which is why electrons fill orbitals like that instead of all clumping at the lowest energy level, prohibits two particles from having all identical quantum numbers. But all muons have muon number 1 and electron number 0, which are by themselves different from electrons, which have muon number 0 and electron number 1, so it's perfectly valid to have a muon and an electron that both have $n=1$, $ℓ=0$, $m_ℓ=0$, $m_s=-½$, even though you can't have two electrons (or two muons) like that.

Answer 3

According to Veritasium, electricity isn't carried by electrons. Electrical power is carried by the Poynting vector, which comes from the electric and magnetic fields. Of course, electrons do affect how the electric field propagates through a material, so if you could make a material in which muons have a similar effect, you could get a flow of electricity.