ICPS 2019 - Our New International System of Units

Public lecture on the occation of the International Conference of Physics Students 2019

Su, 11.08.2019 10:30  –   Su, 11.08.2019 11:45
Prof. Dr. Klaus von Klitzing, Max Planck Institute for Solid State Research, Stuttgart
University of Cologne
Greinstraße 4, 50939 Köln, Germany
Event partner:
University of Cologne
Contact person:
Matthias Dahlmanns,
DPG Association:
Working Group "Young DPG" (jDPG)  
External Link:


On World Metrology Day 2019 (20.5.2019) all countries in the world changed the definitions for the following base units of the International System of Units (SI system): the kilogram, the ampere, the kelvin and the mole. In an historic vote on 16.11.2018, the General Conference on Weights and Measures, which represents 98% of the world gross product, decided this change unanimously. This decision means that all SI units will now be defined in terms of constants of nature. This change was optimized in such a way, that nearly nothing happened in our daily life but in the field of high precision measurements, some adjustments were necessary and more importantly, the new international system of units will be more stable.

The quantized Hall resistance (Nobel Prize 1985) played a crucial role for the realization of this new SI system since this quantum resistance can be used not only for high precision measurements of electrical standards but also for a new realization of a kilogram by comparing electrical and mechanical forces with the Kibble balance.

The talk summarizes the application of the quantum Hall effect in metrology with the focus on the replacement of the kilogram by a fixed value for the Planck constant.

Organisation and Patronage

The Organising Committee being the local conference organisers is supported by the young German Physical Society (jDPG) as well as the International Association of Physics Students {iaps}.
Official Organiser are the University of Cologne and Institute for Theoretical Physics of the University of Cologne.

The Deutsche Physikalische Gesellschaft (DPG) has taken over the patronage for the International Conference of Physics Students 2019.