German physicist who was awarded the Nobel Prize for Physics in 2001, shared with US physicists Eric A Cornell and Carl E Wieman, for his study of Bose-Einstein condensation and his production of a Bose-Einstein condensate in a dilute gas of alkali-metal atoms.
Ketterle and his team at the Massachusetts Institute of Technology, in a series of experiments independent of similar work being carried out by Cornell and Wieman at the University of Colorado, succeeded in producing a Bose-Einstein condensate of a dilute gas of over 20,000 sodium atoms. Ketterle was the co-inventor of the Dark SPOT atom trap, which he used to hold a dilute gas of atoms together, and pioneered laser and evaporative cooling techniques that were later used to cool dilute gas collections to within a few billionths of a degree above absolute zero. He succeeded in producing a Bose-Einstein condensate that contained 20 times the number of atoms achieved earlier by Cornell and Wieman and was able to carry out measurements on the properties of the condensate. By releasing from his condensate, at a controlled rate, single atoms all in the same quantum energy state, he also succeeded in producing the world's first atom laser.
Ketterle's discoveries provide opportunities for the study of fundamental quantum-mechanical systems, which could lead to the application of Bose-Einstein condensates in the fields of lithography, holography, and nanotechnology.
Ketterle was born in Heidelberg. He received his PhD from the University of Munich in 1986, after which he carried out postdoctoral work at the Max Planck Institute in Garching, the University of Heidelberg, and the Massachusetts Institute of Technology (MIT). Ketterle joined the physics faculty at MIT in 1993, where he was later appointed John D MacArthur Professor of Physics. He is a fellow of both the American Academy of Arts and Sciences and the American Physical Society.