Linking the International System of Units to Fundamental Constants

Institutskolloquium

  • Datum: 07.06.2019
  • Uhrzeit: 09:00 - 10:30
  • Vortragende(r): Prof. Dr. Joachim Ullrich
  • Joachim Ullrich studied geophysics and physics at Frankfurt University. He held positions at GSI, Darmstadt, at the Kansas State University, the University of Missouri, was chair of Experimental Physics at the University of Freiburg, before he was appointed a Director at the Max-Planck Institute for Nuclear Physics in Heidelberg. Since 2012 he is the President of the German National Metrology Institute, PTB. He has published more than 590 research papers and received several awards. Among them the Leibniz Award of the Deutsche Forschungsgemeinschaft (DPG), the David Bates Medal of the London Institute of Physics and the Philip Morris Research Award. He is a Fellow of the American Physical Society, an External Scientific Member of the Max-Planck Society, member of the German Academy of Science and Engineering, member of acatech, member of the Berlin-Brandenburg Academy of Sciences and Humanities and Vice President of the German Institute for Standardization, DIN. In 2012 he became a member of the International Committee for Weights and Measures (CIPM) of the Meter Convention and was elected Vice President of the CIPM in 2015 and is the President of the Consultative Committee for the International Units (CCU).
  • Ort: Garching und Greifswald
  • Raum: Hörsaal D2 (Übertragung nach HGW S1)
  • Gastgeber: IPP
In November 2018, the General Conference for Weights and Measures, CGPM, established by the Metre Convention in 1875, decided on the revision of the International System of Units (SI). The signatory states of the Metre Convention represent about 98 % of the world's economic power and, thus, the SI is the very foundation of global, international trade and the reliability of measurements worldwide. As suggested by Max Planck when postulating the "Planck constant" in 1900, the revised SI shall be based on fixing the numerical values of "defining constants": the velocity of light, the elementary charge, the Boltzmann, Avogadro and the Planck constants, the Cs hyperfine clock transition and the luminous efficacy. The revision is based on our present theoretical understanding of the microscopic world and is meant to ensure that the units are valid and realizable "for all times and civilizations, throughout the Universe" as envisioned by Max Planck. The talk will give an overview on the revised SI and its advantages as compared to the previous definitions, focusing in particular on future perspectives for innovative technologies. The question of whether the "defining fundamental constants" are indeed constant in time and the topic of next generation clocks will be addressed briefly.
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