Bose-Einstein condensate

1. The first experiment to see a Bose-Einstein condensate (BEC) in atomic matter was not at MIT but in JILA at the University of Colorado at Boulder by Eric Cornell and Carl Wieman and their group. See http://jilawww.colorado.edu/bec/ for the press release and a list of their publications. I believe the key reference is: "Observation of Bose-Einstein Condensation in a Dilute Atomic Vapor," M.H. Anderson, J.R. Ensher, M.R. Matthews, C.E. Wieman, and E.A. Cornell, Science 269, 198 (1995). The MIT group published results of their BEC observation four months later in "Bose-Einstein condensation in a gas of sodium atoms," K. B. Davis, M.-O. Mewes, M. R. Andrews, N. J. van Druten, D. S. Durfee, D. M. Kurn, and W. Ketterle, Physical Review Letters, 75, 3969 (1995).

2. (Responding to a now-deleted write-up which wrote that a quark-gluon plasma was an example of a Bose-Einstein condensate, I wrote the following...)
   The quark-gluon plasma is not even remotely a Bose-Einstein condensate, nor is the normal confined phase of hadrons a Bose-Einstein condensate. Quarks are fermions, not bosons. It is posited that at high temperatures (not energies) quark matter undergoes a phase transition from the normally confined hadronic phase, quarks confined to be in bound states like the proton, neutron or pion, to a phase where quarks and their force carriers, the gluons, are deconfined and are a gas of free particles. Since quarks are fermions and have spin angular momentum equal to 1/2, they obey Fermi-Dirac statistics, not Bose-Einstein statistics. Futhermore, the existence of the quark-gluon plasma has yet to be seen experimentally. Hints have been seen at CERN, the collider facility in Geneva, but we now await a signal at the Relativistic Heavy Ion Collider or RHIC on Long Island, NY.

Update: Eric Cornell (JILA/Colorado/NIST), Carl Wieman(JILA/Colorado), and Wolfgang Ketterle (MIT) were awarded the 2001 Nobel Prize in Physics for their creation of an atomic Bose-Einstein condensate in the laboratory. A short article chronicling the JILA and MIT efforts to create the BEC appears in the December 2001 issue of Physics Today.

These Bose-Einstein Condensates really illuminate some of the fundamental physics of the universe, one particular experiment, performed by JILA, is perhaps as interesting as it is puzzling.
Take a 'traditional' BEC of ⁸⁵Rb and cool it to only 3 billionths of a degree above zero, and then adjust the magnetic field which holds the condensate in place. Theoretically, the magnetic field should alter the way the wavefunction of the condensate self-interacts, making it either 'repulsive' or 'attractive'. Therefore, you should see the cloud of atoms pulse in and out as you adjust the field.

What actually happened when the experiment was performed, was that, yes, as you make the self-interaction repulsive, the cloud swells as predicted by theory; but when made attractive, the cloud does at first contract, but then suddenly explodes outwards! This 'explosion' (actually about 1500 of the atoms are heated to 200 billionths of a degree so the energy is very small) has a lot of characteristics of a supernova, leading to the coining of the term 'Bosenova'. It produces a shell of atoms, or collimated jets that expand outwards looking like photos of stellar explosions, but interestingly about half the atoms seem to vanish; they're not in the gas of the explosion, or in the remnant left behind! Most likely either the atoms are in a form that's undetectable, or have been given so much energy, they've shot out of the magnetic trap entirely. But who knows, perhaps you are confining the atoms to a state they shouldn't be in and they genuinely disappear, or quantum tunnel out of the trap or even our universe.
(Weird! I hope it doesn't turn out to be an experimental error, and I'm sure it won't; this group is good)

Recently BEC have been used to model a variation of black holes; gravastars in an attempt to use quantum mechanics to explain macroscopic objects at extreme energy scales...