EINSTEIN STRIKES AGAIN

By MICHAEL D. LEMONICK

For three days Eric Cornell kept rechecking his computer, not quite willing to believe what his eyes and his instruments were telling him. There on the screen was a dense knot of something that had appeared in a cloud of rubidium atoms. Finally, Cornell had to acknowledge that it could mean only one thing: he and his colleagues had created a new form of matter, predicted by Albert Einstein more than 70 years ago but never before seen on earth. Called a Bose-Einstein condensate, it is a kind of "superatom," in which individual atoms lose their separate identities and merge into a single entity.

When Cornell and fellow physicists at the JILA laboratory (formerly the Joint Institute for Laboratory Astrophysics) in Boulder, Colorado, announced their achievement in Science last week, their colleagues around the world were quick to cheer. "The term Holy Grail seems quite appropriate, given the singular importance of this discovery," wrote Oxford physicist Keith Burnett in a commentary that accompanied the report.

The physicists' excitement comes partly from the intellectual pleasure of seeing an important scientific loose end tied up at last. When Einstein first suggested the idea of BEC back in the 1920s, building on the work of the Indian physicist Satyendra Nath Bose, quantum mechanics was a new and controversial field. Among its stranger assertions -- long since confirmed -- was that atoms and other elementary particles can also be thought of as waves. The waves are really waves of probability, which describe where an atom is most likely to be at a given moment (Heisenberg's uncertainty principle dictates that you can never say precisely where an atom actually is).

Einstein argued that as atoms approach absolute zero (-459.67 degrees F), the waves expand and finally overlap; the atoms merge into a single "quantum state." It's extraordinarily difficult to get them to 180 billionths of a degree above absolute zero, though -- the point at which the merging occurs. Thus the Boulder group's feat was a technical as well as a scientific one.

They started by barraging their rubidium atoms with lasers, slowing them to a crawl (heat is really just the motion of atoms and molecules; slowing therefore equals cooling). Then they put the atoms in a magnetic "bottle" that allowed the faster-moving, more energetic atoms to escape; those left behind were cooler. Finally, in a leap of ingenuity that enabled this scientific team to outflank its rivals, the Boulder scientists rotated the magnetic field so that the few cold atoms that were leaking through a weak point in the bottle couldn't find this one escape route.

Does any of this have any practical use? Perhaps. Beams of BEC atoms might be used to inscribe exquisitely small circuits onto the ultra-compact electronic chips. The atoms might also be put to work in ultra-precise atomic clocks. So far, the list of applications is not very long. But, says Oxford's Burnett, "it's like the beginnings of laser technology. It's a solution in search of a problem." Given the thousands of ways lasers are used today, that sounds pretty promising.

With reporting by J. Madeleine Nash/Chicago