The Bose-Einstein condensate (BEC) is one of the five primary states of matter. In it, atoms reach such low energies that the rules of quantum mechanics dictate that they stop acting as individual atoms and behave like a single "super atom."
A Bose-Einstein condensate forms only when materials are cooled to within a hair of absolute zero. At that temperature the atoms are hardly moving relative to each other; they have almost no free energy to do so. The atoms then begin to clump together, and enter the same energy states. They become identical, from a physical point of view, and the whole group starts behaving as though it were a single atom.
