01 January 1970 16 2K Report

Is the Fine-Structure Constant the Most Fundamental Physical Constant?

The fine-structure constant is obtained when the classical Bohr atomic model is relativisticized [1][2]. α=e2/ℏc, a number whose value lies very close to 1/137. α did not correspond to any elementary physical unit, since α is dimensionless. It may also be variable [6][7]*.

Sommerfeld introduced this number as the relation of the “relativistic boundary moment” p0=e2/c of the electron in the hydrogen atom to the first of n “quantum moments” pn=nh/2π. Sommerfeld had argued that α=p0/p1 would “play an important role in all succeeding formulas,” he had argued ‡ [5].

There are several usual interpretations of the significance of fine structure constants [3].

a)In 1916, Sommerfeld had gone no further than to suggest that more fundamental physical questions might be tied to this “relational quantity.” In Atomic Structure and Spectral Lines, α was given a somewhat clearer interpretation as the relation of the orbital speed of an electron “in the first Bohr orbit” of the hydrogen atom, to the speed of light [5].

b) α plays an important role in the details of atomic emission, giving the spectrum a "fine structure".

c) The electrodynamic interaction was thought to be a process in which light quanta were exchanged between electrically charged particles, where the fine-structure constant was recognized as a measure of the force of this interaction. [5]

d) α is a combination of the elementary charge e, Planck's constant h, and the speed of light c. These constants represent electromagnetic interaction, quantum mechanics, and relativity, respectively. So does that mean that if G is ignored (or canceled out) it represents the complete physical phenomenon.

Questions implicated here :

1) What does the dimensionless nature of α imply? The absence of dimension means that there is no conversion relation. Since it is a coupling relation between photons and electrons, is it a characterization of the consistency between photons and charges?

2) The various interpretations of α are not in conflict with each other, therefore should they be unified?

3) Is our current interpretation of α the ultimate? Is it sufficient?

4) Is α the most fundamental physical constant**? This is similar to Planck Scales† in that they are combinations of other fundamental physical constants.

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Notes

* Spatial Variation and time variability.

‡ Sommerfeld considered α "important constants of nature, characteristic of the constitution of all the elements."[4]

† https://www.researchgate.net/post/NO30The_Relation_Between_Mathematics_and_Physics_6-Are_Planck_Scales_Constants_Parameters_or_Principles

** https://www.researchgate.net/post/No28The_Relation_Between_Mathematics_and_Physics_4-Could_All_Physical_Constants_be_Unified_to_a_set_of_Fundamental_Constants_of_Nature

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References

[3] 张天蓉. (2022). 精细结构常数. https://blog.sciencenet.cn/blog-677221-1346617.html

[1] Sommerfeld, A. (1916). The fine structure of Hydrogen and Hydrogen-like lines: Presented at the meeting on 8 January 1916. The European Physical Journal H (2014), 39(2), 179-204.

[2] Sommerfeld, A. (1916). Zur quantentheorie der spektrallinien. Annalen der Physik, 356(17), 1-94.

[4] Heilbron, J. L. (1967). The Kossel-Sommerfeld theory and the ring atom. Isis, 58(4), 450-485.

[5] Eckert, M., & Märker, K. (2004). Arnold Sommerfeld. Wissenschaftlicher Briefwechsel, 2, 1919-1951.

[6] Wilczynska, M. R., Webb, J. K., Bainbridge, M., Barrow, J. D., Bosman, S. E. I., Carswell, R. F., Dąbrowski, M. P., Dumont, V., Lee, C.-C., Leite, A. C., Leszczyńska, K., Liske, J., Marosek, K., Martins, C. J. A. P., Milaković, D., Molaro, P., & Pasquini, L. (2020). Four direct measurements of the fine-structure constant 13 billion years ago. Science Advances, 6(17), eaay9672. https://doi.org/doi:10.1126/sciadv.aay9672

[7] Webb, J. K., King, J. A., Murphy, M. T., Flambaum, V. V., Carswell, R. F., & Bainbridge, M. B. (2011). Indications of a Spatial Variation of the Fine Structure Constant. Physical Review Letters, 107(19), 191101. https://doi.org/10.1103/PhysRevLett.107.191101

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