Wilfrid POIRIER - Advanced quantum standards for electrical units

Wednesday, April 8, 2026
1:30pm — amphi Jaurès - 29 rue d'Ulm 75005 PARIS

Advanced quantum standards for electrical units

The recently revised International System of Units (SI) enshrines modern physics by establishing definitions of units based on the fixed values of seven physical constants, including the Planck constant h and the elementary charge e. The ampere, the base electric unit, is now linked to e, and no longer to the newton, enabling realization of electrical units with exceptional accuracy using quantum phenomena. The Josephson effect and the quantum Hall effect have particularly revolutionized the electrical metrology by providing accurate realizations of the volt and the ohm from 2e/h and h/e² constants, respectively, with a relative uncertainty below 10^-9. Continuous progresses of nanofabrication, of instrumentation and discovery of new materials such as graphene [1] or magnetic topological insulators enable metrologists to develop quantum voltage and resistance standards that are more practical and versatile, with broader applications. The realization of the ampere, which means controlling a defined flow of elementary charges, remains challenging with a target measurement uncertainty below 10^-8. Recently, we have developed a programmable quantum current generator [2] based on the application of Ohm’s law to quantum voltage and resistance standards combined in a quantum circuit involving a superconducting cryogenic amplifier. Currents are generated at quantized values of ±(n/p)ef_J with record relative uncertainties below 10^-8, where n and p are integer control parameters and f_J is the Josephson frequency [3]. At the heart of a complete quantum instrumentation comprising several quantum devices, the new quantum current standard lays the foundations for a universal quantum realisation of the electrical units of voltage, current and even resistance, within a single experiment [4]. 

[1] R. Ribeiro-Palau et al, Nat. Nanotechnol. 10, 965 (2015) 

[2] J. Brun-Picard et al, Phys. Rev. X 6, 041051 (2016). 

[3] S. Djordjevic, R. Behr and W. Poirier, Nat. Commun. 16, 1447 (2025).

[4] W. Poirier and S. Djordjevic, Nat. Electron 8, 632 (2025)