Seminario - Revision of the International System of Units (SI) and Electrical Quantum Metrology

Contatto di riferimento: Marco Crescentini

About the speaker

Dott. Luca Callegaro holds a degree in Electronic Engineering (1992) and a Ph.D. in Physics (1996), both from Politecnico di Milano, Italy. He joined the Istituto Nazionale di Ricerca Metrologica, INRIM, Torino, Italy, in 1996. He is head of the Nanoscience and Materials Division of INRIM, and adjunct professor of electronic measurements at Politecnico di Torino. His research interests are focused on electrical impedance, and he is responsible for the Italian National standards of electrical capacitance, inductance, ac resistance and ac voltage ratio. He is chairman of the Technical Committee for Electricity and Magnetism (TC-EM) of EURAMET, the European Association of National Metrology Institutes. He is author of about 90 papers on international reviews and of the book Electrical impedance: principles, measurement and applications, CRC Press: Taylor and Francis

Abstract

The International System of units (SI) is the basis of modern-day measurements. On 16 November 2018 the General Conference of Weights and Measures has approved a major revision of the SI. All the seven base units are defined in terms of a fundamental constant of nature, which have an exact value. It is possible to realize the SI units everywhere and every time, by probing with experiments these fundamental constants. Electrical units are defined in terms of the elementary charge e and the Planck constant h; it is possible to realize the volt, ohm and ampere by quantum experiments in solid-state devices. The kilogram, redefined in terms of h, can be realized by counting atoms in a silicon sphere, or by linking it to the quantum realization of the electrical power unit, the watt. The new SI is enforcing since May 20, 2019.