Quantum electrodynamics 1986 adjustment

Abstract. A review is given of the latest adjustment of the values of the fundamental constants. The new values are recommended by the Committee on Data for Science and Technology (CODATA) for international use. Most of the fundamental constants are obtained by the comparison of the results of critical experiments and the corresponding theoretical expressions based on quantum electrodynamics (QED). An important case is the Rydberg constant which is determined primarily by precise frequency measurements in hydrogen and deuterium. 

The 1998 adjustment of the values of the fundamental physical constants has been carried out by the authors under the auspices of the CODATA Task Group on Fundamental Constants [1,2]. The purpose of the adjustment is to determine best values of various fundamental constants such as the fine-structure constant, Rydberg constant, Avogadro constant, Planck constant, electron mass, muon mass, as well as many others, that provide the greatest consistency among the most critical experiments based on relationships derived from condensed matter theory and quantum electrodynamics (QED) theory. The 1998 CODATA recommended values of the constants also may be found on the Web at physics.nist.gov/constants. 

Some of the predicted transition frequencies have an uncertainty more than an order of magnitude smaller than that of the Lande factor g of the electron, which was previously the most accurate prediction of quantum electrodynamics (QED). These predictions were obtained by combining accurately measured transitions in hydrogen and deuterium with recent QED calculations. A mostly non-technical overview of the relevant adjustment procedures is given in this paper. 

Several classifications have been introduced. The earliest seems to have been according to estimates of overall uncertainty. This is particularly useful in reducing complexity in the adjustment process if one group of experiments is significantly more accurate than a second group whose members are of approximately equal (and lesser) estimated accuracy [5]. A second type of classification partitioned the input measurements into a class whose data reduction required use of quantum electrodynamics in a significant way and the remainder which did not. This separation was particularly informative when the Josephson 2e/h measurement allowed for a choice between values for the fine-structure constant as derived from fine-structure and hyperfine structure in hydrogen [6]. 

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