The Quantum Revolution in Metrology
The worldwide introduction on May 20, 2019, of an International System of Units based on constants of nature realized a vision of Max Planck. His theoretical explanation of the blackbody radiation included two new fundamental constants, known today as Planck and Boltzmann constants, which enabled the formulation of Planck units for length, mass, and time. However, these units were not useful for practical applications in metrology. This changed, however, with the discovery of two quantum phenomena, the Josephson effect and the quantum Hall effect. The talk will present new insights into how the quantum Hall effect has entered this field.