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The SI and Quantum Metrology



Carl J. Williams


The United States’ National Institute of Standards and Technology (NIST) is playing a major role in the worldwide effort to base the International System of Units (SI) on fundamental constants. In many cases, units will be redefined in terms of invariant quantum phenomena. So to a great degree, the progress of modern metrology will depend on our ability to make increasingly sensitive, accurate, and repeatable measurements of quantum processes. Within NIST, that effort is the responsibility of an organization called the Physical Measurement Laboratory (PML). PML’s core mission is to realize, disseminate, and advance the SI in the United States. PML seeks to ensure that the SI is maintained and improved, realized in practice, disseminated for routine uses, and disseminated for new and novel uses. And it is at the forefront of the measurement science required to enable the impending redefinition of the SI units, planned for 2018.
Proceedings of the International School of Physics “Enrico Fermi” Vol. 196
Publisher Info
IOS Press, Amsterdam, -1


International System of Units, Quantum Based Measurements, Quantum Metrology


Williams, C. (2017), The SI and Quantum Metrology, Proceedings of the International School of Physics “Enrico Fermi” Vol. 196, IOS Press, Amsterdam, -1 (Accessed May 22, 2024)


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Created December 1, 2017, Updated June 25, 2018