A New Measure: The revolutionary, quantum reform of the modern metric system
Abstract:
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:
Prof. William D. Phillips is an American physicist at the National Institute of Standards and Technology (NIST). In 1997, along with Steven Chu and Claude Cohen-Tannoudji, he won the Nobel Prize in Physics for his contributions to laser cooling. This technique allows slowing down the movement of gaseous atoms in order to better study them. He also invented the Zeeman slower. Bill Phillips is also Professor of physics at the University of Maryland, College Park, USA.
The Spring DPhyMS colloquia will continue with the new format:
- The Department is pleased to offer a networking coffee break for those attending the colloquium, starting at 15:30h (after the talk) in the main Hall of BSC. This will be a wonderful opportunity to interact with the speaker and your colleagues, so please join us for this informal gathering.
- For organizational reasons, please register by Tuesday 13 May 2025 for the lunch on 16 May 2025.
- Online – through Webex – to give you the opportunity to listen to the talk in case you are travelling or cannot make it onsite at Campus Limpertsberg. Here are the details to join the talk online: Meeting number: 2784 212 9522 Password: YNy7GG5nGb4