A new type of quasiparticle – dubbed the "leviton" – has been seen by physicists in France and Switzerland. First predicted in 1996 by a team led by Leonid Levitov, the phenomenon involves the excitation of as few as one electron to create a wave that propagates coherently through a metal. The ability to make levitons on demand could lead to the creation of quantum-electronics circuits that involve sending single electrons through tiny circuits.
I tell ya, the 2D electron gas universe is just so rich, we will discover a whole lot more. We already have seen fractional quantum hall effect in such a system, and it may even exhibit signs of Luttinger liquid properties. So I will not be surprised if there are more to come.