Innsbruck Physics Lecture - Tue, 22 Oct. 2019, 17:15 lecture hall A 
Joachim Ullrich – Physikalisch-Technische Bundesanstalt Braunschweig


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).

Linking the International System of Units to Fundamental Constants


In November 2018, the General Conference for Weights and Measures, CGPM, established by the Metre Convention in 1875, decided in its 26thmeeting 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 outlined by Max Planck in his famous paper of 1900 postulating the “Planck constant”, 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 of time, for all people”, the vision formulated during the French revolution, extended by Max Planck “for all times and civilizations, throughout the Universe”. 

In the talk an overview will be provided on the revised SI, its advantages as compared to the previous definitions, focusing in particular on future perspectives with improved realization of the units exploiting innovative technologies. If time allows the question if the fundamental constants used as “defining constants” are indeed constant in time.  Next-generation clocks bear the promise to trace potential changes in the fine structure constant aat the level of Da/a»10-20per year.


Previous lectures

Francis Halzen, IceCube: Opening a New Window on the Universe from the South Pole. >>
(30 Oktober 2018)

(17 Oktober 2017)

Paul Corkum, Probi6g quantum systems from the inside – on the attosecond time scale >>
(10 November 2016)

Alain Aspect, Institut d'Optique Graduate School, Palaiseau, France >>
(10 November 2015)

Michael Kramer - Nearly 100 years after General Relativity: Was Einstein right? >>
(04 November 2014)

Immanuel Bloch - Controlling and Exploring Quantum Matter at the Single Atom Level >>
(22 October 2013)

Wim Ubachs - Search for a variation of fundamental constants >>
(13 November 2012)

Reinhard Genzel - Massive Black Holes and Galaxies >>
(4 October 2011)

Nach oben scrollen