Bose–Einstein condensate Theory
 Particles can only have a set amount of energy. They either have the energy to bounce around in gases or just the energy to flow like a liquid or be fixed like a solid. If you take enough of the particle's energy away you get to the tiniest or the smallest amount of energy possible. This makes all of the particles exactly the same and instead of bouncing around randomly in all different directions, they all bounce up and down in exactly the same way, forming something called a 'giant matter wave'.