Researcher in metrology
Workshop : Can we access an objective representation of time?
Sébastien Bize is CNRS researcher at SYRTE - Observatoire de Paris. His research focuses on highly accurate atomic frequency standards and their applications. One important application, implemented at SYRTE within the framework of the French national metrology network coordinated by LNE, is the elaboration of the French legal time reference UTC(OP) and of the international atomic time (TAI). Atomic frequency standards are also used to test fundamental laws of physics and to search for dark matter. Novel optical atomic frequency standards are emerging as new tools for geodesy and geophysics. Also, they may lead to a redefinition of the second of the international system of units.
Precise time scales are key resources for science and modern society. These time scales can be described as our attempt to obtain an objective representation of physicist’s time. Concepts underpinning the definition and the realization of modern atomic time scales will be described. These concepts enable the realization of the International Atomic Time (TAI) and of the Universal Coordinate Time (UTC). Virtually, 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. In the last 2 decades, a novel generation of optical atomic clocks emerged that is 100 times better than the ones currently used in TAI & UTC. These references offer novel opportunities. Practical time scales also have limits that make them differ from an ideal representation of time.