Number 237 (Story #1), August 15, 1995 by Phillip F. Schewe and Ben Stein BOSE-EINSTEIN CONDENSATION (BEC) OF LITHIUM ATOMS has been demonstrated by physicists at Rice University (Randall Hulet, 713-527-6087). Like the condensation of rubidium atoms (reported last month, Update 233), the condensation of the much lighter lithium atoms begins with cooling to nanokelvin temperatures in an atom trap employing both laser beams and magnets. The Rice researchers believe that their gas of Li atoms passes over into the Bose- Einstein state---in which as many as 100,000 atoms coalesce into a single atomic state---at a temperature between 400 and 100 nK. They measure the temperature and density by passing a laser beam through the trapped atom cloud and recording the shadow cast by the atoms. BEC is detected by the diffraction of the probe light from the small (several microns in diameter) condensate. The formation of the Bose-Einstein state in Li atoms was somewhat of a surprise because it was thought that the very weak interaction (the so called van der Waals force) between atoms in the gas phase---attractive in the case of lithium, repulsive in the case of Rb---might cause the atoms to condense into a conventional liquid or solid rather than to the BEC state. The Rice scientists surmise that the zero-point energy of the Li atoms, the energy possessed the atoms at even the lowest of temperatures by virtue of the Heisenberg uncertainty principle, was able to overcome any van der Waals interaction, allowing the BEC state to form. (C.C. Bradley et al., 38 Aug. 95, Physical Review Letters. For science writers only: text and figures are available from AIP Public Information, physnews@aip.org)