Ross Anderson
6.4K posts
@Cure_The_CDC
Physicist -Interfaith Interpreter - Friend -
Einstein believed in an eternal and unchanging universe. But the Dutch physicist Willem de Sitter was more open-minded. He realized that an evolving universe was a natural consequence of Einstein’s theory. quantamagazine.org/in-expanding-d…
🌌 In five dimensions, the vector potential IS gravity. Kaluza showed in 1921 that extending spacetime from four to five dimensions makes the electromagnetic four-potential Aμ appear as off-diagonal components of the five-dimensional metric tensor g₅μ. The metric tensor. The object that defines the geometry of spacetime in general relativity. The vector potential is literally a piece of the gravitational field in one extra dimension. In this formulation, gauge transformations ARE coordinate transformations in the fifth dimension. Electric charge IS momentum in the fifth dimension. Klein extended this in 1926 by compactifying the fifth dimension to Planck-scale radius, making it unobservable while preserving its physical effects. Two of the deepest theories in physics become one theory in five dimensions. The consequence for the deletion thesis: when you gauge-fix the electromagnetic potentials, you are constraining gravitational degrees of freedom in the Kaluza-Klein framework. Deleting degrees of freedom from Aμ simultaneously deletes components of the higher-dimensional gravitational field. The superpotential formulation makes this precise: the gravitational potential Φg is related to ∇·A. Precisely the term the Lorenz gauge eliminates. If ∇·A carries gravitational information, then gauge-fixing electromagnetism simultaneously hides gravitational physics. Li and Torr showed that in a superconductor, the same Cooper pair condensate that physically fixes A (London gauge) may simultaneously fix the gravitational vector potential Ag. The electromagnetic-gravitational bridge may be a physical coupling mediated by the same condensate. The GEM analogy has experimental confirmation: Gravity Probe B measured frame-dragging at 37.2 ± 7.2 milliarcseconds per year. Moving mass generates a gravitational analogue of the magnetic vector potential. Section 4.10 of my paper "The Deleted Degrees of Freedom" develops the full Kaluza-Klein argument and the superconductor bridge. Section 5.3 covers gravitational engineering implications. Free. Pinned on my profile.
