> One of the simplest quasiparticle is the "electron hole". Take a lattice of some electrically neutral substance. Remove one electron from it. There is now an "electron hole" in it. You can treat that hole like a particle now. It can "move" to another location by having the real electrons change places. It can "flow" through a series of such events. You can model a lot of things with "electron holes" that act in very particle-like ways. But they don't exist on their own. This one is simple because you don't even need quantum mechanics to get a hold of it in your head.

An electron hole seems like a simple, almost silly idea at first. Isn't it just like the hole in a sliding puzzle game. You move a neighbouring electron into the hole, so the hole disappears and a new hole appears at the neighbouring position. It seems to "move". Does this deserve a special name like "quasi-particle"?

But it's not like the hole in a sliding puzzle!

An electron hole moves with inertia, like a real particle. It behaves as if it has mass: You can push it and it starts moving. If you push it more, it accelerates more. But unlike a sliding puzzle, when you stop pushing, the electron hole carries on moving at the same speed.

It keeps going by itself in whatever direction it was going, until it's pushed in a different direction, or bounces off something.

You can't push a sliding puzzle hole at a diagonal angle, let alone push it that way and then watch the puzzle hole keep on moving that way by itself like an independently moving object, as far as it can go until it hits something.

If you had a large sliding puzzle with two holes, you wouldn't expect to be able to send them towards each other, bounce off each other and continue.

And you certainly can't perform double slit interference with sliding puzzle holes. You can, in principle (hard in practice), make electron hole beams and interfere them.

Things like holes and other patterns in matter behave remarkably like real, coherent particles, even though they are just patterns.