XLIII National Congress of the Italian Society for the History of Physics and Astronomy

Celestial micro-mechanics 1916-17: Einstein vs. Schwarzschild, Sommerfeld, Epstein

6 Sept 2023, 10:25

20m

Aula Rosino (DFA - Astronomia)

SISFA 2023 Da Poleni a B. Rossi e oltre / From Poleni to B. Rossi, and Beyond: 20th Century

Speaker

AFRIAT, Alexander (Université de Bretagne Occidentale)

Description

I compare two resarch programmes from the late years (1916-) of the old quantum theory. In three texts from 1917, Einstein proposes an apparently Hamiltonian micro-mechanics – on a torus designed to ‘Riemannize away’ problematic dynamical multi-valuedness – characterised by surprisingly modern invariances: ‘point’ (diffeomorphic) and homotopic. The rival programme (Schwarzschild, Sommerfeld, Epstein etc.), which is genuinely canonical, produces its own tori through action-angle variables and uses perturbations (Zeeman, Stark, relativity) to eliminate awkward coordinate ambiguities which would affect quantisation itself.