Small but important correction: two conducting plates. https://en.wikipedia.org/wiki/Casimir_effect https://en.wikipedia.org/wiki/Casimir_effect Also works in

Small but important correction: two conducting plates. https://en.wikipedia.org/wiki/Casimir_effect https://en.wikipedia.org/wiki/Casimir_effect Also works in other geometries, e.g., sphere and plate, two spheres, etc. First experimental verification was a sphere and a plate, I think? https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.78.5 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.78...