William D. Phillips - CREOL Spring Colloquium Talk (February 13, 2026)

Описание: A New Measure: The revolutionary, quantum reform of the modern metric system

The International System of Units (the SI), the modern metric system, recently underwent its most revolutionary change since its origins during the French Revolution. The nature of this revolution is that all of the base units of the SI are now defined by fixing values of natural constants. Our measurement system is now, both philosophically and practically, decidedly quantum. This talk will recall some of the history of how units have been defined in the past, describe why the quantum reform was needed, and how it is done.

About the Speaker: William D. Phillips received a B.S. from Juniata College in 1970, and a Ph.D. from MIT in 1976; after two years as a postdoc at MIT, he joined NIST to work on precision electrical measurements and fundamental constants. There, he founded NIST’s Laser Cooling and Trapping Group, and later was a founding member of the Joint Quantum Institute, a cooperative research organization of NIST and the University of Maryland. His research group has developed some of the principal techniques used for laser-cooling and cold-atom experiments in laboratories around the world. Atomic fountain clocks, based on the work of this group, are now the primary standards for world timekeeping. The group also studies quantum information applications of cold atoms.

Dr. Phillips is a fellow of the American Physical Society, the American Association for the Advancement of Science, and the American Academy of Arts and Sciences. He is a Fellow and Honorary Member of OPTICA, a member of the National Academy of Sciences, the Pontifical Academy of Sciences, and a corresponding member of the Mexican Academy of Sciences. In 1997, Dr. Phillips shared the Nobel Prize in Physics "for development of methods to cool and trap atoms with laser light."