Ketterle, Wolfgang, KEHT er luh, VOHLF gahng (1957-...), a German physicist, won a share of the 2001 Nobel Prize in physics for his experiments on a state of matter known as a Bose-Einstein condensate (BEC). A BEC is a cluster of atoms that behave somewhat as if they were a single atom. Ketterle shared the prize with the American physicists Eric A. Cornell and Carl E. Wieman. BEC's are named for the physicists Satyendra Nath Bose of India and Albert Einstein of Germany, who proposed in the 1920's that BEC's could be created.