Kaluza without Klein

A 100 years ago Theodor Kaluza noticed that you can express Maxwell’s equations with the tools of differential geometry of Geneneral Relativity. You will get both EM and GR in 5D. The results do not fit to particle properties and that prompted Oskar Klein to try to combine the concepts with quantum mechanics, hence the theory is known as Kaluza-Klein-Theory today.
Referring Kaluzas ansatz in first approximation to electromagnetism only and imposing spin of one half as boundary condition yields precise particle mass, gravitation can be recovered by a series expansion. The approach is supported by a simple particle model which allows to identify the elementary fermions of the standard model of particle physics with a specific set of rotations in 3D-space.
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