Wolfgang Ketterle
active c. 1957, Heidelberg, Germany
German physicist who created Bose–Einstein condensates in sodium with record atom numbers and demonstrated interference between two condensates.
Ketterle studied at Heidelberg and earned his PhD in Munich in 1986 on molecular spectroscopy, then did postdoctoral work at Boulder before joining MIT in 1990, where he remains professor of physics.
Months after the Cornell–Wieman group, his MIT team achieved Bose–Einstein condensation in sodium vapor with millions of atoms — thousands of times more than the first sample — enabling the observation of interference fringes when two condensates overlapped (1997), direct evidence of macroscopic coherence. He shared the 2001 Nobel Prize in Physics and went on to pioneer ultracold Fermi gases, cold molecules, and optical lattices.
Nobel-winning work
In late 1995, Ketterle's MIT group used a 'cloverleaf' magnetic trap and evaporative cooling to condense over 10 million sodium atoms — a sample large enough for quantitative study of condensate properties: collective oscillations, vortices, phase coherence.
In 1997 he split one condensate in two and let them overlap: interference fringes appeared, proving that two clouds of millions of atoms still behave as coherent matter waves — a direct consequence of a single macroscopic quantum state. He also built an 'atom laser' releasing a coherent de Broglie wave beam from the trap. The 2001 Nobel was shared with Cornell and Wieman.
Workplaces: Massachusetts Institute of Technology (MIT)
Germany, United States