What Makes Quantum Metrology "Quantum"? From Fundamental Constants to Quantum Measurement

Seton J. Bennett

Paul H. Cutler, Lucas, Armand A

P.H. Cutler, Amand A. Lucas, Jakub Kłeczek

G. Rosi

In this paper, after a short theoretical introduction, we are going to discuss the application of matter-wave interferometry to the precise measurement of two important physical constants: the Newtonian gravitational constant G and the fine-structure constant α. This capability of determining the strength of so different fundamental interactions (gravity and electromagnetism) makes such technique one of the most versatile investigation methods available.

Shisong Li

In November 2018, during the 26th General Conference on Weights and Measures (CGPM) in Versailles, France, a landmark resolution was adopted to redefine four base units of the International System of Units (SI)(https://www.bipm.org/en/committees/cg/cgpm/26-2018/resolution-1). The kilogram, mole, ampere, and kelvin were redefined in terms of fundamental physical constants: the Planck constant$(h)$, the Avogadro constant$(N_{\mathrm{A}})$, the elementary charge$(e)$, and the Boltzmann constant$(k)$, respectively. As illustrated in Figure 1(a), the new SI framework defines all seven base units based on fundamental constants, marking a complete transition of metrology into the quantum era. This system has been in effect globally since May 20, 2019, on World Metrology Day.

Mauro Paternostro, Diogo de Oliveira Soares Pinto