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The role of fundamental constants in redefining the SI

Celebrating the work accomplished towards the proposed redefinition of the International System of Units (SI) in terms of physical constants, the BIPM organized a scientific symposium on 7 September 2017 under the auspices of the Consultative Committee for Units (CCU). During the symposium The fundamental constants of physics: what are they and what is their role in redefining the SI, participants recognized the work accomplished so far through a series of leading-edge lectures.

Now, we are close to adopting a set of fundamental constants as the basis for our unit system, it is inspiring to consider what we will learn as our understanding of physics continues to develop, commented Dr Martin Milton, Director, BIPM.

The distinguished line-up of speakers featured Dr Gilles Cohen-Tannoudji, the Nobel laureate Prof. Klaus von Klitzing, Prof. Jean Marc Lévy-Leblond, Dr Terry Quinn, Dr Jean-Philippe Uzan, and Prof. Gabriele Veneziano.

Nobel laureate Professor Klaus von Klitzing during his lecture at the BIPM
Nobel laureate Professor Klaus von Klitzing during his lecture on The quantum Hall effect and the revised SI.

Topics ranged from the profound nature of the different fundamental physical constants and the different types of fundamental constants to their role in the evolution of physical theory, more specifically gravitation, cosmology and in string theory. Additionally, the role the fundamental constants play in the upcoming revision of the SI was examined.

A selection of these lectures is available at:

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