Mötesplats Rydberg: Prefekten informerar + Andreas Wacker: Revolutionary change in SI-units: Quantum mechanics is ruling the weight of objects from 20 May 2019!
Revolutionary change in SI-units: Quantum mechanics is ruling the weight of objects from 20 May 2019!
Andreas Wacker
Units like the meter, kilogram, or ampere are of utmost importance for our society as manifested, e.g., by their relevance for trade or the documentation of scientific research. The SI-system, which is the worldwide standard defining these units, is revised on the 20 May 2019 in order to improve the accuracy and reproducibility. Mostastonishingly, the kilogram will not be represented by the prototype
from 1889 any longer, but is defined by attributing a fixed value to Planck’s constant. Thus, quantum mechanics is now ruling the weight of objects! Of equal importance is the change in the ampere, so that the vacuum permeability is no longer exactly 4 pi*10^{-7)N/A^2. Please update your lecture slides!
Decision of the 26. General Conference on Weights and Measures: https://www.bipm.org/en/CGPM/db/26/1/
Talk by W. Phillips at this conference https://www.bipm.org/utils/common/pdf/CGPM-2018/Presentation-CGPM26-Phillips.pdf