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I recently came across a concept in quantum physics called Quasiparticles. They seemed interesting so, I did a little bit of research about them. However, I still don't understand what they are. The Wikipedia page described them as "collective excitations of particles", but I didn't understand what that means.

Could someone please post a simplified explanation of what quasiparticles are? Is there some kind of table like the standard model that organizes them?

Akhilesh Balaji
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1 Answers1

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Fundamental particles are excitations of fundamental fields.

A quasiparticle is an excitation of a multi-particle system. The difference between these and elementary particles is that quasiparticles cannot exist outside of a multi-particle system.

A good example are semiconductor holes where many electrons that move in one direction result in the appearance of a positive hole moving in the opposite direction. This positive hole is termed a quasiparticle.

Other examples of quasiparticles are phonons, exitons and plasmons.

I’m not sure if there is a table$^1$ of quasiparticles. If there was, it would not be similar to the standard model since quasiparticles are a consequence of a system of particles, unlike the particles of the standard model.

$^1$ Edit: After answering another question regarding quasiparticles, I happened to come across this article on Wikipedia which lists and describes (with links to) the various known quasiparticles.

joseph h
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    It's probably worth pointing out that also electrons in semiconductors are quasiparticles in the single-electron approximation. – Massimo Ortolano Jan 27 '21 at 08:05
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    @MassimoOrtolano That is an interesting remark. Does it perhaps warrant its own answer? – Peter - Reinstate Monica Jan 27 '21 at 15:53
  • @Peter-ReinstateMonica I really don't have much time these days for a proper answer, but it's essentially the concept expressed in this one. A discussion about this, among many other books, can be found in Cohen, Marvin L.; Louie, Steven G.. Fundamentals of Condensed Matter Physics, Cambridge University Press, which gives a list of quasiparticles in solids with their description. – Massimo Ortolano Jan 28 '21 at 07:35
  • @MassimoOrtolano not only in single-particle approximation - e.g., also in Landau Fermi liquid (e.g., see here https://physics.stackexchange.com/a/648292/247642) – Roger V. Aug 26 '21 at 07:40