2 Groups of Physicists Produce Matter That Einstein Postulated
By MALCOLM W. BROWNE
Published: July 14, 1995
By chilling a cloud of atoms to a temperature barely above absolute zero, scientists at a Colorado laboratory have at last created a bizarre type of matter that had eluded experimenters ever since its potential existence was postulated by Albert Einstein 70 years ago.
The creation of this Bose-Einstein condensate -- named for Einstein and the Indian theorist Satyendra Nath Bose -- was hailed yesterday as the basis of a new field of research expected to explain some fundamental mysteries of atomic physics.
A Texas group later produced similar results. The achievement should allow physicists to peer directly into the realm of the ultrasmall.
In a comment being published today by the journal Science, Dr. Keith Burnett, a physicist at Oxford University in England, said, "The term Holy Grail seems quite appropriate, given the singular importance of this discovery."
Details of the achievement were disclosed in a technical paper published by Science and at a news conference yesterday in Boulder, Colo.
Separately, a research team led by Dr. Randall G. Hullet (pronounced HEW-it) of Rice University in Houston, announced yesterday that it had independently created a Bose-Einstein condensate made of atoms different from those used in the Colorado laboratory and using a somewhat different method.
A Bose-Einstein condensate is a gas of atoms that have been so chilled that their normal motion is virtually halted. In this almost stationary condition, the wavelengths of individual atoms -- the dimensions that define the regions in which they may be found -- grow to relatively enormous size, overlapping each other and merging into a kind of super atom. This merged atom, despite growing to a range of sizes typical of those of bacteria, obeys the rules of quantum mechanics, the physics of the ultrasmall.
The creation of this unique state of matter by the Colorado group occurred on June 5, when a microscopic blob of Bose-Einstein condensate abruptly appeared in the glass vessel containing super-cold rubidium atoms. The condensate was destroyed when a laser probe flashed through it, but it survived long enough to leave its image on a computer screen. The scientists withheld news of the momentous achievement until yesterday to allow time for independent researchers to study and evaluate their results.
(There is no formal definition of the term "state of matter," although gases, liquids and solids are clearly different states of matter. The Colorado group said that distinctions between states are fuzzy, and that a Bose-Einstein condensate could be regarded as a substate of gas.)
The Rice team said that it reached the elusive condensation goal on Tuesday and that its results were still preliminary.
The Colorado team, known as JILA, from the surviving acronym for the former name of the laboratory, the Joint Institute for Laboratory Astrophysics, is a research coalition of the National Institute of Standards and Technology at Boulder with the University of Colorado. Money for the project came from the standards institute, the National Science Foundation and the Office of Naval Research.
Dr. Eric A. Cornell of the standards institute, a leader of the Colorado team, said: "I could hardly believe we actually had it, under just the conditions that had been predicted. It was like a dream come true."
Dr. Cornell described the Bose-Einstein condensate as a kind of matter analogous to a laser beam. In a beam of ordinary light produced by a flashlight, the wave-particles of energy known as photons behave chaotically in a variety of mismatched "quantum states." By contrast, the photons in a beam of laser light march in lockstep with each other, behavior described as "coherent." Similarly, ordinary atoms in a cloud of gas exist in a chaotic state, but in a Bose-Einstein condensate, they are coherently matched with each other, sharing a common quantum-mechanical wave function and losing their individual identities.
Atoms merged with each other in this intimate way to form super atoms represent a kind of bridge between the everyday world of normal objects and the ultrasmall world of atoms and elementary particles, ruled by the peculiar laws of quantum mechanics. This bridge, physicists hope, will make it much easier to study such quantum mechanical phenomena as superconductivity (the ability of some materials to conduct electrical current without any resistance) and superfluidity (the ability of certain fluids to flow through even the thinnest channel with no impeding resistance). When liquid helium is chilled to about two degrees above absolute zero it becomes a superfluid that scientists believe exhibits some of the manifestations of Bose-Einstein condensates.
The world's first verified Bose-Einstein condensate, which physicists believe has never existed in nature anywhere in the universe, occurred when the laboratory's table-top apparatus forced the atoms inside it to a record low temperature of 170 one-billionths of a degree above absolute zero. With further cooling, the laboratory drove down the temperature still further, to as low as two one-billionths of a degree