The 2001 Nobel Prize in Physics

The 2001 Nobel Prize in Physics goes to Eric Cornell of NIST/JILA, Wolfgang Ketterle of MIT, and Carl Wieman of Colorado/JILA (JILA is an institute run jointly by NIST and the University of Colorado). Cornell and Wieman are recognized for their being the first to achieve a Bose-Einstein condensate (BEC) in neutral atoms (Science, 14 July 1995; see Physics News Update 233). Ketterle soon thereafter produced a larger BEC (Davis et al., Physical Review Letters, 27 November 1995) and has made extensive study of BEC properties.

The BEC phenomenon, foreseen by Satyendra Bose and Albert Einstein in the 1920s, can come about when atoms are chilled to very low temperatures. Quantum theory holds that the wavelike nature of atoms allows them to spread out and even overlap. Indeed at a high enough density and a low enough temperature (billionths of degrees above absolute zero) the atoms can, like the photons in a laser, enter into a common quantum state with a common energy. In other words, the atoms are all coordinated (coherent) with each other and constitute a single "super atom."

BEC was possible experimentally when in a magneto-optic trap (MOT), a combination of laser cooling (a web of laser beams hitting the atoms from many directions) and evaporative cooling (a web of magnetic fields encourage the warmer atoms to depart, leaving the cooler atoms to coalesce in the trap) brought about unprecedentedly low temperatures. BEC is still largely restricted to fundamental research in physics labs, but numerous potential applications beckon, such as the use of BEC beams ("atom lasers") for doing high-resolution lithography for microchips, interferometry (navigation, gravity wave detectors, etc.), high-precision clocks, and "atomtronics" (atoms sent around a microchip or down hollow fibers).

Physics News Update has covered BEC research extensively. Examples include BEC as a superfluid (Update 449), rudimentary atom laser (305), amplifying atom waves (465), all-optical BECs (545), switching BEC interactions from negative to positive (producing miniature "supernovas," Update 530), BEC on a microchip (559), BEC as an immiscible liquid (402), hydrogen BEC (382), lithium BEC (237), helium BEC (532), tunable chemistry (362), sound waves in BEC (319), slowed light in a BEC (472), quantum evaporation (356), and continuous atom laser beam (422). (Background: Wieman and Cornell, Scientific American, March 1998; see also Royal Swedish Academy press release.)