nLab Stern-Gerlach experiment

Redirected from "Beck's theorem".
Note: monadicity theorem and monadicity theorem both redirect for "Beck's theorem".

Contents

Idea

The Stern-Gerlach experiment showed that electrons are spinors. It was the first experimental observation of the elementary spin $\frac{1}{2}$ of fermions.

Via the Pauli exclusion principle/spin-statistics theorem, this implies that wavefunctions depending on fermionic variable commute with each other only up to a sign, forming a supercommutative superalgebra. This way the Stern-Gerlach experiment is ultimately the observation that physical reality is described by supergeometry.

(Notice that there is supergeometry independently of supersymmetry, which may or may not be present in addition).

The original article:

Walther Gerlach, Otto Stern: Der experimentelle Nachweis der Richtungsquantelung im Magnetfeld, Zeitschrift f¨r Physik 9 (1922) 349–352 [doi:10.1007/BF01326983]

and its English translation:

Martin Bauer: The Stern-Gerlach Experiment, Translation of: “Der experimentelle Nachweis der Richtungsquantelung im Magnetfeld” [arXiv:2301.11343]

Review:

Last revised on April 11, 2026 at 23:27:01. See the history of this page for a list of all contributions to it.