Local spinor structures in V. Fock's and H. Weyl's work on the Dirac equation (1929)

Abstract

In early 1929, V. Fock (initially in collaboration with D. Iwanenko) and H. Weyl developed independently from each other a general relativistic generalization of the Dirac equation. In the core, they arrived at the same theory by the introduction of a local (topologically trivial) spinor structures and a lifting of the Levi-Civita connection of underlying space-time. They both observed, in slightly different settings, a characteristic underdetermination of the spin connection by a complex phase factor, which gave the symbolical possibility for a reformulation of Weyl's old (1918) idea to characterize the electromagnetic potential by a differential form transforming as a gauge field. Weyl and Fock realized the common mathematical core of their respective approaches in summer 1929, but insisted on differences in perspective. An interesting difference was discussed by Weyl in his Rouse Ball lecture in 1930,. He contrasted the new type of unification strongly to the earlier geometrically unified field theories (including his own). He was quite explicit that he now considered his earlier ideas on geometrization of ``all of physics'' as premature and declared that the new, more empirically based approach would have to go a long way before it could be considered as a true "geometrization" of matter structures.