This article presents a brief history of the appearance of electron spin in relativistic wave equations. Dirac derived his wave equation in 1928 with the intention to obtain an equation for the "simplest" particle with spin zero. But, as Dirac later announced at the European Conference on Particle Physics (Budapest, 4—9 July 1977), it was a big surprise for him that the equation described the states of a particle with spin 1/2.

Keywords: spin, relativistic wave equations PACS: 01.65.+g, 03.65.−w (all) DOI: 10.3367/UFNe.2019.11.038695 URL: https://ufn.ru/en/articles/2020/7/g/ 000575189200007 2-s2.0-85092533766 2020PhyU...63..721P Citation: Petrov S V "Was Sommerfeld wrong? (To the history of the appearance of spin in relativistic wave equations)" Phys. Usp. 63 721–724 (2020) BibTexBibNote ® (generic)BibNote ® (RIS) MedlineRefWorks PT Journal Article TI Was Sommerfeld wrong? (To the history of the appearance of spin in relativistic wave equations) AU Petrov S V FAU Petrov SV DP 10 Jul, 2020 TA Phys. Usp. VI 63 IP 7 PG 721-724 RX 10.3367/UFNe.2019.11.038695 URL https://ufn.ru/en/articles/2020/7/g/ SO Phys. Usp. 2020 Jul 10;63(7):721-724 Received: 9th, September 2019, accepted: 11th, November 2019 Оригинал: Петров С В «Ошибался ли Зоммерфельд? (К истории появления спина в релятивистских волновых уравнениях)» УФН 190 777–780 (2020); DOI: 10.3367/UFNr.2019.11.038695