Sébastien Bize

Biography

Sébastien Bize is a CNRS researcher at the Système de référence temps-espace (SYRTE) at Paris Observatory. His research focuses on high-accuracy frequency atomics and their applications. An important application, implemented at SYRTE as part of the French national metrology network coordinated by the Laboratoire national de métrologie et d’essais (LNE), is the development of the reference for French legal time, Coordinated Universal Time, UTC(OP), and international atomic time (TAI). Atomic frequency standards are also used to test the fundamental laws of physics and to search for dark matter. New atomic standards, known as optical frequency standards, are emerging as new tools for geodesy and geophysics. What’s more, they could lead to a redefinition of the second in the international system of units.

Conference: Can time be represented objectively?

Accurate time scales are essential resources for modern science and society. These time scales can be described as our attempt to obtain an objective representation of physicists’ time. The concepts underlying the definition and realization of modern atomic time scales will be described. These concepts enable the realization of International Atomic Time (TAI) and Coordinated Universal Time (UTC). In practice, we are all users of these time scales. This is possible because a variety of means make these time scales accessible to users and applications. Over the past two decades, a new generation of optical atomic clocks has emerged, 100 times more powerful than those currently used in TAI & UTC. These references open up new opportunities. Practical time scales also have limitations that make them different from an ideal representation of time.