[gradschoolfail]

The way my inner child handwaves it away: you have the electron wavefunction spread out, say, it’s equally likely to be in one of 2 points in space. If you only look at one of these 2 points, you are likely to measure only half an electron.. until an adult (say, you) corrects me (using the Feynman Dirac hand/belt trick)

[johncarlosbaez]

That explains having a 50% chance of seeing an electron somewhere, not seeing an entity of charge 1/2. It's like a weather report saying there's a 50% chance of rain doesn't mean you're going to see little raindrops cut in half.

[gradschoolfail]

If you look at the experiments, they don’t mention observing a single entity of fractional charge, it is always in terms of aggregate behavior under EM fields: conductance(1) inferred from shot noise (2), or density (3)

(1) https://arxiv.org/pdf/0912.4868

(2) https://n.ethz.ch/~marnikm/files/shotNoise.pdf

(3) https://www.researchgate.net/profile/Gerhard-Abstreiter/publ...

Personally, I find it curious that people talk about detecting single photons, but in these fractional charge experiments, nobody mentions detecting a single quasiparticle.

As for the math, nobody says it outright, or even in a single paragraph, but a fractional charge (“filling fraction”) of p/q does correspond to p “normal” charges distributed over q degenerate states (q=2 equivalent locations I used in the naive example)

https://xgwen.mit.edu/sites/default/files/documents/topWN.pd...

[zmgsabst]

> Personally, I find it curious that people talk about detecting single photons, but in these fractional charge experiments, nobody mentions detecting a single quasiparticle.

You detect a single photon when it perturbs an apparatus like a photon multiplier; you detect a single quasiparticle when it perturbs a split stream of electrons.

The apparent difference is that photons can travel through free space and strike such an apparatus from afar; while quasiparticles definitionally cannot. However, I’ve read about experiments that measure a single anyon on a dot by wrapping electron interferometry around it, which is measuring the lone quasiparticle on that dot.

So I don’t follow your point.

[gradschoolfail]

Thank you for keeping me on my feet!

You probably mean the following (note the nuance and date of the first one):

https://arxiv.org/pdf/2403.12139.pdf

https://www.nature.com/articles/s41567-020-1019-1

I still think my point, originally about 1 electron split into 2 locations, or “ends” of string (but devolving to a complaint about casual ignorance of the central issue in publications) hasn’t been completely destroyed, because here you are measuring interference of 2 anyons, somewhat like measuring the interference of a photon “with itself” in a double split experiment.

The broader point could be that the effect of a single photon is “localized”, but here to see the effect, you have to move 1 anyon in a “complete path” around the other, recalling the Feynman/Dirac belt in my top level comment, a trick I said an adult should try to correct me with :)

[marcosdumay]

There is only a difference if you observe the position.

When interactions happen only between particles that are all spread through that same space, both look the same.