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Just to be clear for a general reader. These are quasiparticles. They are effective mathematical descriptions of certain effects in the real world, but the phys
by ivalm 6y ago
Just to be clear for a general reader. These are quasiparticles. They are effective mathematical descriptions of certain effects in the real world, but the physical particles responsible for the effects are fermions and bosons, not anyons.
- Koshkin 6y agoBut the article also says, If it seems strange to call the collective behavior of electrons a particle, think of the proton, which is itself made up of three quarks.
- deleted 6y ago[deleted]
- ivalm 6y agoAbsolutely! Just wanted to highlight. It is easier to think of stable and localized collective behaviors (protons) as particles than unstable and delocalized (anyons). Both are collective behaviors but most of the time you can think of protons as “balls made of quarks.” It’s not quite right but with semi classical treatment you get most of the effects. Anyons are not even approximately balls made of electrons. They break a lot of “classical particle” intuition the way protons don’t.
- xvilka 6y agoBut if you think of them as the waves, any kind of close and stable wave superposition can be called "a particle". At some point, we might just drop the "particle world" and go with the "quantum systems".
- ivalm 6y agoMost people have an intuition about particles, they don’t have an intuition for quantum systems. I wanted to highlight for a general reader that anyons are not particle in the sense of common intuition. Protons, which the article brings as an example of collective phenomenona, roughly follow a lot of “particle intuition.”
- state_less 6y agoHere is a link to the quasiparticles Wikipedia page that may be helpful. https://en.m.wikipedia.org/wiki/Quasiparticle https://en.m.wikipedia.org/wiki/Quasiparticle Personally, I don’t mind if folks reify these things to make it easier to follow, fwiw.
- adrianN 6y agoI wonder whether we could change school curricula so that people develop an intuition about quantum systems instead. I my schooling I learned almost exclusively particle abstractions. It's only natural that I'm more comfortable with particles.
- DagAgren 6y ago> Most people have an intuition about particles That intuition is also most likely completely wrong.
- stared 6y agoIn this case, electric current is NOT carried by electrons. Electrons in a material are effective particles, with a different mass, vide https://en.wikipedia.org/wiki/Effective_mass_(solid-state_physics) https://en.wikipedia.org/wiki/Effective_mass_(solid-state_ph.... Partice != fundamental particle.
- knzhou 6y agoYeah. In this case it's fine, but in general it can lead to confusion. For some weird reason, condensed matter physicists keep giving their quasiparticles the same names particle physicists give their particle particles, even though the mathematics are quite different. If you hear someone proclaiming the discovery of Majorana fermions, axions, or monopoles, it's essentially guaranteed to be a quasiparticle in a lump of metal or something. Sometimes even the articles themselves get confused about this.
- twic 6y agoIs this really so different from particle physicists' "resonances", where they see a peak in a graph and pronounce a new particle: https://en.wikipedia.org/wiki/Resonance_(particle_physics) https://en.wikipedia.org/wiki/Resonance_(particle_physics)
- knzhou 6y agoThat's fine because basically everything's a resonance. The only particles that aren't technically resonances are those that have infinite lifetime, i.e. just the proton, electron, and photon.
- whatshisface 6y agoThe "weird reason" is that it's an analogy. You want to name things in a way that people will be able to guess what they are from the name.
- contravariant 6y agoIn addition the proper term would be fundamental particles for the regular quarks/bosons. It's somewhat debatable whether quasiparticles are physical or not.
- badrabbit 6y agoWhat else would they be?
- Retric 6y agoArbitrary classifications like national borders.
- contravariant 6y agoEmergent phenomena. Like how a row of toppling dominos will have a front which seems to move through the dominos, but is actually just a long chain of mostly stationary dominos. It would be odd to argue the front is a physical object. Taking this further you might conclude that a soundwave isn't physical either. And sound is actually an examples of quasiparticles (phonons) when you get down to the quantum level. Then again most people would be of the opinion that light propagates slower through solids like glass, but the photons in that description are quasiparticles (which have mass, unlike the photons in isolation). And quasiparticles share many properties that you'd normally expect only physical particles to have so it gets complicated.
- ivalm 6y agoI said "physical" because I wanted to include things other than elementary particles but that behave in a way consistent with what I think is a typical non-physicist general intuition about particles: "somewhat long lived (sufficient to be resolved not just by decay products) point-like objects". Some elementary particles (quarks) don't really obey a lot of this intuition. Some none-elementary particles, for example protons/neutrons, do follow a lot of this intuition. Even some topological order quasiparticle in CMP follow this intuition -- magnetic skyrmions can be localized, can be imaged, have particle-like scattering. Anyons don't follow this particle intuition.
- adrian_b 6y agoEven if these are interesting research results, in my opinion, "anyon" is a stupid word choice. It might have been a good joke initially, but it should not have persisted as a scientific name. The termination "-on" in the Ancient Greek words "electron" and "proton" does not have any concrete meaning, it is just the thematic vowel "o" followed by the marker "n", of a singular neuter noun (originally "m", but in Ancient Greek all final "m" became "n"). Combining some undeclinable English word with an Ancient Greek case termination seems ugly and pointless for me (not that "fermion" and "boson" are any better from this point of view). Even if we accept making words to rhyme as a technique for coining new words, "anyon" remains a bad choice, because it is easily confused with "anion" (introduced by Faraday almost two hundred years ago). I assume that "anyon" is meant to have a different pronunciation, i.e. like "any-on", but nonetheless, in almost all other languages the vowels are pronounced different than in English and the default pronunciation for "anyon" and "anion" will likely be the same.
- whatshisface 6y agoWait, why is ancient Greek a justifiable basis for evaluating the language evolution of modern English?
- adrian_b 6y agoLike I have said, the main problem is the too great similarity to an existing word, which is expected to be used in the same contexts. The reference to Ancient Greek is a matter of taste, I prefer new words to either have a meaning or to have no meaning, i.e. to be random. I find words with nonsense meaning irritating and more difficult to remember. At least "fermion" is just a distorted form of Fermi, which does not suggest any specific meaning. On the other hand "any on", has a meaning, but a nonsensical one, i.e. its suggests a reference to any one of the "ons", but there is no such thing as an "on", as that is just a grammatical case marker. By the way, the "-on" in "anion" is not the same as the "-on" in proton. While the "-on" in proton comes from "-om", the "-on" in anion comes from "-ont", which corresponds to the English "-ing", the suffix of the active participle (anion = upwards-going).
- at_a_remove 6y agoYes, every time I hear about a new class of whatever, with surprising properties, I check to see if they're talking about quasiparticles. And they're almost always talking about quasiparticles. Now, there's nothing wrong with exploring those ideas and they might eventually be fruitful, but in terms of looking "further down" (which is typically the lure of the excitement), quasiparticles are only looking back up. I am of the mind that you could make assemblages of particles -- that is to say, quasiparticles -- do all kinds of oddball things that their constituents cannot. That is fine and often useful, but it isn't the further down we were interested in.