Summerfield (Arnold Sommerfeld) - Investigator site log

Run 2026-10-09 (first run)

Web time used: about 9.5 minutes (cap 10). Chrome connected; searches in Google via Chrome, page fetches by script where sites allowed it. Notes per site in research/2026-10-09-*.md; downloads in research/files/.

Stance: the "inventor" here is Arnold Sommerfeld, author of the mainstream 1923 textbook in the folder. The run looked for his own fuller statements of the claims (the 1915-16 papers, other editions, letters), for the measurements and dissent around the hydrogen fine structure, for related quantisation work, and for the historical record. No verdicts.

Keywords tried

• Sommerfeld "Atombau und Spektrallinien" 1922 third edition archive.org
• Gehrcke Lau hydrogen fine structure Sommerfeld relativity 1920 anti-relativist
• "Sommerfeld puzzle" fine structure formula Dirac coincidence old quantum theory
• Sommerfeld Briefwechsel online Paschen Feinstruktur 1915 Deutsches Museum Sommerfeld-Projekt
• Kragh "fine structure of hydrogen and the gross structure of the physics community" 1916-26 Robotti 1986
• Houston 1937 Williams 1938 Pasternack hydrogen H-alpha fine structure discrepancy before Lamb shift history
• site:nobelprize.org nomination archive "Arnold Sommerfeld" nominee
• Gehrcke Lau Feinstruktur Wasserstoff Relativitätstheorie Abraham starres Elektron 1921 1924
• "Lau" "Feinstruktur" Wasserstofflinien Bericht 1924 Physikalische Zeitschrift Feinstrukturkonstante
• Ishiwara 1915 Wilson quantum condition phase integral independent of Sommerfeld history
• Paschen 1916 He+ 4686 fine structure reanalysis spin Dirac agreement Sommerfeld "wrong reasons"
• jstor Kragh 1985 "The Fine Structure of Hydrogen and the Gross Structure of the Physics Community"
• Robotti 1986 hydrogen fine structure Paschen Sommerfeld history article
• archive.org advancedsearch: creator:(Sommerfeld) AND title:(Atombau OR spectral OR Spektrallinien OR Quantentheorie); title:("Annalen der Physik") 1916-1917; identifier sim_annalen-der-physik_1921_65*; creator:(Paschen) 1910-1930
• arXiv API: id_list 2506.00408, 2401.07485, 1708.04676; ti:"fine structure of Weber's hydrogen atom"
• Sommerfeld-Projekt person index: Paschen, Gehrcke, Glitscher, Brose; subject index F (Feinstruktur: no entry)
• HathiTrust catalog: "Atombau und Spektrallinien"
• de.wikipedia API: Ernst Gehrcke
• Untried for later runs: Brose Methuen 1923 translation; "Wasserstoffdublett" Paschen 1916; Merton 1920 hydrogen fine structure; McLennan fine structure 1924; van Cittert Feinstruktur; Hansen 1925 Houston; Millikan Bowen 1924 relativity doublets; Landé Röntgendubletts Polemik; Sommerfeld Nobel nomination 1926 Paschen text; Epstein 1916 Stark effect; Rubinowicz 1918 selection rule; Kossel; Wentzel; Biedenharn 1983 Foundations of Physics "Sommerfeld puzzle"; Yourgrau; "Atomic Structure and Spectral Lines" review 1923 Nature.

Leads for review

1. The inventor's own work

• Sommerfeld to Paschen, 23 May 1924 (transcription online): privately says the relativistic theory is secured by the number and position of the components, "Aber die Grösse von [Delta nu] = 0,365 möchte ich nicht mit gleicher Sicherheit behaupten"; proposes a nucleus-electron mutual-mass effect that would make the doublet smaller; takes Lau's result on the higher He+ analogues seriously; urges new measurements of the fine-structure constant. Bears on claims 2 and 6. [web] https://sommerfeld.userweb.mwn.de/TransDat/02183.html
• Sommerfeld to Paschen, 29 Dec 1915 (draft): ratios of hydrogen differences agree "vortrefflich", but "die Absolutwerte nicht" (0.102 predicted against 0.24). Bears on claim 2 (how the fit to Paschen's data was built). [web] https://sommerfeld.userweb.mwn.de/TransDat/00585.html
• Sommerfeld 1915 Sitzungsbericht (first statement of the fine structure, CC BY PDF saved) and Sommerfeld 1916 Annalen treatise, parts I and II (saved). In 1916 he notes that Paschen's impulsive discharge appears to lift the quantum inequalities, and uses it for the "ideal" hydrogen doublet. Bears on claims 1-3. [web] research/files/
• Other editions for checking misprints and retractions: German 1921 (archive.org, open), German 1922 (HathiTrust full view, edition to confirm), English 1934 (archive.org, open), single-page scan of the 1923 English edition (archive.org, saved), which may make the outstanding deep reads easier. Bears on all claims; on the "Corrections" list in claims.md.

2. Supporting information by others

• Paschen 1916, "Bohrs Heliumlinien" (full text saved): before Sommerfeld's theory his hydrogen/helium data gave e/mu = 1.74 against 1.76 +/- 0.01; with "friendly help" of the theory's creator the whole material was brought into "genügende Übereinstimmung". Paschen to Sommerfeld, May 1916: "agree everywhere most beautifully". Bears on claim 2 (the experimental support and how it was obtained). [web]
• The "Sommerfeld puzzle" (Vickers 2018; Suslov 2024; Barley et al. 2025; Biedenharn 1983): Sommerfeld's 1916 energy formula is exactly the Dirac 1928 result; Heisenberg called it a "miracle", Schrödinger "a fortuitous computational accident", Biedenharn traced it to an underlying symmetry. Bears on claims 1, 2, 6. [web]
• Eckert (2013, 2014), Kragh (2025): history of the third edition (over 4,000 copies within a year; "the bible"), of the Paschen collaboration, and of the "doublet riddle" (Millikan's 1924 ultraviolet data extending the relativistic doublet formula to optical spectra). Bears on claims 2, 5, 7. [web]

3. Closely related work

• Ishiwara 1915 and Wilson 1915: the same phase-integral quantum condition found independently (claim 1). [web] arXiv 1708.04676.
• Glitscher 1917 (Munich dissertation, Annalen 52): the Abraham-vs-Lorentz-Einstein spectroscopic test proposed by W. Lenz; source of the 4/5 factor in claim 6. [web]
• Frauenfelder and Weber 2019: Bohr-Sommerfeld fine structure for Weber's electrodynamics (a non-relativistic velocity-dependent force law), agreeing with Wesley's Schrödinger-equation result. An alternative dynamics put through the same quantisation; bears on whether the fine structure singles out special relativity (claim 6). Not read. [web]

4. Historical record

• Gehrcke and Lau 1921 (PTR; full text saved): measured hydrogen Delta nu "etwa um 25 Proz. kleiner" than Sommerfeld's value, no measurement error apparent, intensity ratio depends on the source. Gehrcke was a leading anti-relativist (his stance, recorded beside his data). Sommerfeld's 1924 letter calls the Abraham alternative "indiscutabel" and the work of "Lenard, Gehrke, Lau" fanatical, yet takes Lau's helium result seriously. Bears on claims 2 and 6: the dissent existed, was measured, and was answered privately with doubt about 0.365 rather than in the book. [web]
• Kragh 1985 (HSPS 15:67-125), the standard study of this dispute (paywalled), and Robotti 1986: not obtained. Houston, Williams 1938, Pasternack: 1930s discrepancies later understood as the Lamb shift (1947, about 0.033 cm^-1); not obtained. These are the records that would show how much of the 1916-24 shortfall had a cause outside the theory.
• Nobel nominations: 84 nominations of Sommerfeld, never awarded; a 1926 nomination jointly with Paschen (Google snippets). The nomination texts would show what the nominators took the fine-structure work to have established. Not read.
• Anti-relativity controversy in the letters (Scheel 1920, Laue 1920, Sommerfeld to Einstein 1920, Volkmann 1925): Sommerfeld, as DPG chairman, in the public dispute with Gehrcke, Lenard and Weyland. [web]

Corrections to earlier documents

• None found wrong. Confirmation: the English edition date 1923, tagged [memory, high] in the deep read (line 5), is confirmed by the archive.org record (New York, Dutton, 1923) [web]. The claims.md note "Whether these [misprints] appear in the German original was not checked" can now be acted on: the German 1921 (archive.org) and probably 1922 (HathiTrust) editions are open.