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What Metrology Gains With Quantized Resistance Standards



Randolph E. Elmquist


The emergence of quantum metrology is expressed in modern electrical standards, primarily through the Josephson effect and the quantum Hall effect. The Josephson and von Klitzing constants that relate to these standards are given in quantum theory by ideal equations KJ = 2e/h and RK = h/e2, respectively. While they are not definitions, these two equalities encompass invariant physical laws and are thought to be valid for certain broad types of quantum mechanical systems. It is well known that these quantum standards can provide epresentations of international electrical units that are equivalent and unchanging in value. This paper describes several recent experiences concerning the quantized Hall resistance (QHR) standard from a viewpoint within a National Measurement Institute (NMI). It describes the measurements of some fundamental constants that are made more accurate because the QHR standard is an unchanging representation of the ohm. The QHR standard has also helped to bring about improved international comparisons of resistance units, as well as the development of better methods of scaling from one resistance level to a higher or lower resistance. A new experiment to compare the Josephson and quantum Hall effects together with a fundamental standard of electric current is described.
Proceedings Title
Proc. Metrologia 2000 Conference
Conference Dates
December 4-7, 2000
Conference Location
Sao Paulo, BR


measurement standards, resistance measurement, Quantum Hall effect


Elmquist, R. (2000), What Metrology Gains With Quantized Resistance Standards, Proc. Metrologia 2000 Conference , Sao Paulo, BR, [online], (Accessed April 18, 2024)
Created December 1, 2000, Updated June 2, 2021