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MYSTERIES OF THE BOSE-EINSTEIN CONDENSATE

In 1995, researchers Eric Cornell and Carl Wieman of the Joint Institute for Laboratory Astrophysics at the University of Colorado (JILA) cooled a handful of gaseous rubidium-87 atoms (approximately 2,000) to less than one degree Kelvin. Zero degrees K is absolute zero, at which point all atomic activity ceases and beyond which things can not be colder. The coldest places in the Universe in the deepest regions of deep space are about 3 degrees K. The work of Cornell and Wieman on rubidium atoms and that of Wolfgang Ketterle of Massachusetts Institute of Technology on sodium atoms earned for them the Nobel Prize for Physics in 2001.

The result of the experiment at JILA was that all the atoms that were cooled to that temperature (about 170 nanokelvins) assumed the same quantum state - termed the ground state of the gas - wherein all the atoms behaved in concert. The wave functions of the atoms that make up this Bose-Einstein Condensate (BEC) overlap. The atoms are said to collapse into what physicists call a "super atom". The properties of a BEC include the complete absence of viscosity, in effect creating a "super-fluid" wherein all the atoms move in the same way therefore losing no energy due to friction when they flow; and the generation of ultra low speed electro-magnetic waves in the optical spectrum, down to about 17 m/s for a sodium BEC. Insomuch as the deBroglie waves of the atoms in a BEC are coherent, they can be compared to laser light wherein the EM waves generated are also coherent.

The creation of a BEC is only possible with particles that have a total spin that is an integer multiple of the Planck constant divided by 2(pi), which defines the boson. The concept of the BEC was developed by Albert Einstein after he reviewed an intuitive paper written by the Indian physicist Satyendra Nath Bose in 1924 which dealt with the behavior of photons in an enclosed space, or black body radiation. Einstein predicted that at sufficiently low temperatures identical atoms or particles would become locked together in the lowest quantum state of the system. This could not be proved until the tools were made available to create the necessary temperatures seventy years later.

The first stage in creating a BEC involves tuning a laser beam array to the exact frequency of the atoms which have been purified by isolation in a chamber. The photon waves that bounce off the atoms acquire velocity in the process, stealing a little energy

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