The Quasi-Quantum Hall Effect

The experiments were in something called the fractional quantum Hall effect, which is a kind of material that is a two dimensional electron gas subject to a very high magnetic field. So you get this very unusual state of matter where the quasi particles are anyons. And what that means is that there's a very unusual kind of interaction as one of these quasi particles moves around another,. We call that braiding, because the world lines make braids and knots. This interaction leads to kind of interference patterns that is what's actually observed.