Fundamental Units: Physics and Metrology

Abstract

Abstract. The problem of fundamental units is discussed in the context of achievements of both theoretical physics and modern metrology. On one hand, due to fascinating accuracy of atomic clocks, the traditional macroscopic standards of metrology (second, metre, kilogram) are giving way to standards based on fundamental units of nature: velocity of light c and quantum of action h. On the other hand, the poor precision of gravitational constant G, which is widely believed to define the "cube of theories" and the units of the future "theory of everything", does not allow to use G as a fundamental dimensional constant in metrology. The electromagnetic units in SI are actually based on concepts of prerelativistic classical electrodynamics such as ether, electric permitivity and magnetic permeability of vacuum. Concluding remarks are devoted to terminological confusion which accompanies the progress in basic physics and metrology.

Dimensions and units in electrodynamics

“…Okun's equations Ref. [43], (20,21,22) have a more restricted domain of applicability: they are only valid in flat Minkowskian spacetime in Cartesian coordinates. A dimensional analysis of Maxwell-Lorentz electrodynamics yields the speed of light c and the wave resistance of the vacuum Ω 0 as the two quantities characterizing the electromagnetic properties of spacetime.…”

“…COMMENTS ON A RECENT PAPER OF OKUN [43] First of all we should say that Okun, at least in the realm of elementary particle physics, expresses the majority view as it is given, e.g., in the textbooks of Feynman [12], Jackson [23], or Landau-Lifshitz [32], see also the discussions of Chambers [5] and Roche [51]. We believe, however, see Secs.IV, V, and VI above and Ref.…”

“…IX. COMMENTS ON A RECENT PAPER OF OKUN [43] First of all we should say that Okun, at least in the realm of elementary particle physics, expresses the majority view as it is given, e.g., in the textbooks of Feynman [12], Jackson [23],…”