Carl E. Wieman, (born March 26, 1951, Corvallis, Oregon, U.S.), American physicist who, with Eric A. Cornell and Wolfgang Ketterle, won the Nobel Prize for Physics in 2001 for creating a new ultracold state of matter, the so-called Bose-Einstein condensate (BEC).

After studying at the Massachusetts Institute of Technology (B.S., 1973), Wieman earned a Ph.D. from Stanford University in 1977. He then taught and conducted research at the University of Michigan in Ann Arbor until 1984, when he joined the faculty at the University of Colorado. In addition to serving as a professor, he directed the school’s Science Education Initiative (2006–13). He headed a similar initiative at the University of British Columbia (2007–13), where he also taught. In 2013 Wieman began teaching at Stanford University.

Wieman’s work on the Bose-Einstein condensate began in the late 1980s. This new state of matter, which had been predicted some 70 years earlier by Albert Einstein and the Indian physicist Satyendra Nath Bose, contains atoms so chilled and slow that they, in effect, merge and behave as one single quantum entity that is much larger than any individual atom. Working with Cornell, Wieman in 1995 used laser and magnetic techniques to slow, trap, and cool some 2,000 rubidium atoms to form a BEC. His work provided insight into the laws of physics and led to research on possible practical uses of BECs.