Strictly speaking, this is not actually particles physics. It is about many particles that interact with each other.

The concept of quasiparticles was developed by Landau to explain the properties of electrons in metals.
As a first approximation, these electrons can be described as gas of particles that do not interact with each other. But to take into account that they are inside a crystal lattice, which affects how they react to external fields, their mass has to be corrected. The result is that the particles used to describe the electric properties of metals are no longer simple electrons, but electron-like particles.

This is similar to the small oscillations in analytical mechanics: close to equilibrium a system can be described in term of a set of oscillators, which are not necessarily parts (or particles) of the system literally oscillating.

And, as a matter of fact, this is directly used in solid state physics. For example, the properties of the crytal lattice close to equilibrium are described in terms of quasiparticles called "phonons", which correspond to the oscillations of atoms. The long-range properties of the electrons in a metal are described in terms of "plasmons", which correspond to long-range oscillations of the charge density of the electrons.

There are many more example in condensed matter physics.

In the case of the OP, we have a gas of electrons confined to a plane and in a strong magnetic field. In this case, the quasiparticles used to describe the system correspond a a number of electrons "bound" to a number magnetic flux quanta. So, if we look at single flux quantum, we can have a fractional electron charge.

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papageno


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