I know! But when you poke it, it still acts like a particle and the wavefunction localizes again, right? It doesn't exactly "puff up" like a billiard ball. Elec

I know! But when you poke it, it still acts like a particle and the wavefunction localizes again, right? It doesn't exactly "puff up" like a billiard ball. Electrons don't really get bigger when they are put into states where their position is less localized. But the expansion of space does "stretch" light- or at least, the wavelength gets longer, so it's not not happening.