Three happy physicists. Ketterle, Cornell, and Wieman (from left to right).

Physics Nobel for Quantum Superparticle

The chilly work of Wolfgang Ketterle, Eric Cornell, and Carl Wieman has gotten a warm reception in Stockholm; this morning the three physicists learned that they've won the 2001 Nobel Prize in Physics for creating the first Bose-Einstein condensates (BECs) in gases of rubidium, sodium, and other alkali metals.

Albert Einstein, building on the work of physicist S. N. Bose, predicted 75 years ago that a gas made of a certain type of particle would behave very strangely when cooled to a few billionths of a degree above absolute zero. When almost all the energy gets sucked out of so-called boson particles, they should stop jittering about and settle down together into the lowest energy state. Then their quantum identities merge and they start behaving, in a sense, like one large particle. This "superparticle" is a BEC, and BECs are playgrounds for bizarre physics. For example, a BEC can slow light down to a crawl.

Several groups had been attempting to coax matter into becoming a BEC, but none succeeded until 1995, when Cornell and Wieman, physicists at the University of Colorado, Boulder, and the National Institute of Standards and Technology, Boulder, used optical and magnetic traps to bully about bosonic rubidium atoms into forming a BEC. Shortly thereafter, Wolfgang Ketterle of the Massachusetts Institute of Technology managed to do the same with sodium atoms, creating a considerably bigger condensate. These achievements set off a flurry of experiments: Scientists used BECs to create "atomic lasers" and watched as vortices formed and dissipated within the BECs. The work continues to give physicists new insights into the nature of quantum interactions. "We've been surprised to see the explosive growth of the field," says Ketterle. "We thought it would be neat, but it has had an enormous impact on atomic physics."

The prize, split evenly among the three winners, comes as no surprise to the physics community. "It's very well deserved," says Claude Cohen-Tannoudji, a physicist at the École Normale Supérieure in Paris, who won the 1997 Nobel Prize in Physics with Steven Chu and William Phillips for developing the cooling technique that allows physicists to make BECs.

Related sites

The Nobel Prize in Physics 2001
Original news of Bose-Einstein condensate
A review of observations and news in Science