William Daniel Phillips
Phillips, William Daniel (1948-) is an American physicist who shared the 1997 Nobel Prize in physics with American Steven Chu and French physicist Claude Cohen-Tannoudji. Phillips works in the field of laser cooling of atoms—using laser beams to slow down the random movements of atoms in a gas until they are nearly stationary, so that they can be more closely studied.
Phillips was born on Nov. 5, 1948, in Wilkes-Barre, Pennsylvania. His parents, Mary Catherine Savino (changed to Savine) Phillip, and William (Bill) Cornelius Phillips, were professional social workers in Pennsylvania's hard coal region. Phillips had one sister and a brother. As a child, Phillips enjoyed science, and his parents encouraged his experimentation. In 1956, the family moved to Butler, Pennsylvania, near Pittsburgh, and later to Camp Hill, near Harrisburg, where Phillips attended high school.
Phillips earned a doctorate at the Massachusetts Institute of Technology. After postdoctoral work there, in 1978 he joined the National Bureau of Standards (later the National Institute of Standards and Technology—NIST) at Gaithersburg, Maryland, where he worked on precise electrical measurements. He also experimented with the laser cooling of atoms.
Atoms move fast in hot materials, slow in cold ones. Phillips showed that a stream of atoms could be slowed with beams of laser light. His investigations grew into a long-term program of research by NIST. In 1985, he and his colleagues succeeded in slowing atoms and trapping them using a magnetic field. The scientists reduced the temperature of an atomic beam from room temperature to 1/10 of a Celsius degree above absolute zero (-273.15 °C).
A few years later, Phillips and his group adopted a new invention, a type of atom trap called a magneto-optical trap, which enabled them to achieve still lower temperatures, about 40 millionths of a Celsius degree above absolute zero. This temperature was lower than scientists had previously thought possible, and theorists had to revise their ideas to account for it. Today, workers in this field have cooled atoms to within a few millionths of a degree of absolute zero.