In 1925 Bengali physicist Satyendra Nath Bose proposed that a new state of matter could exist, based on his work in quantum mechanics. It took seventy years before Eric Cornell and Carl Wieman, at the University of Colorado, managed to make it.
Known as a Bose-Einstein condensate, the new matter was essentially a collection of atoms so cold that they behaved like one large "superatom," demonstrating quantum mechanical effects on a macro scale. The science of the super cold has been hard to switch from theory to practice because the art of getting matter to fractions of a degree above absolute zero is far from simple. Indeed, many of the methods involved have been as groundbreaking as the scientific results they have yielded.
A critical step was the invention of the magnetic atom trap, proposed in 1983 in a research paper by David Pritchard (b. 1941). It relies on the principle of quantum mechanics stating that the magnetic moment of an atom is "quantized"—that is, it has to take a discreet value, 'rather than have a continuous range of values available. The magnetic atom trap employs a magnetic gradient, and thus has the range to trap neutrally charged atoms.
In the creation of Bose-Einstein condensates, atoms are required that are already extremely cold. Physicists have various methods of cooling atoms, such as using lasers in a magneto-optical trap. But for the ultra-low temperatures needed to form a Bose- Einstein condensate, the magnetic atom trap was the perfect solution. It was able to hold the atoms "captive" while evaporative cooling was used to push the temperature low enough to create this promising new form of matter.
