Many Worlds made sense to me as a solution when I considered the case of an apparently random choice. Instead of the world collapsing on an arbitrary choice, each world gets one choice. In the case of interaction with a propagating wave of light, though, I don’t see how it would work. Perhaps something is incorrect with my fledgling model of light.
Let’s consider a single photon. That would still propagate as a spherical wave from the source. The wave expands uniformly from the source and I suppose that according to a classical theory (?), that wave could be perceived simultaneously by different people in different places around the source. Even if I interact with the wave by moving an electron that approximately cancels that wave, then my cancellation would propagate only at the speed of light, not instantaneously.
I suppose that according to a classical theory (?), that wave could be perceived simultaneously by different people in different places around the source.
That is indeed what the classical theory says. It is wrong. This is where the assumption that domain of the amplitude is continuous is a bad approximation.
So how would Many Worlds work in this case?
Quantum amplitude flows into separate configurations. For each detector, there is a configuration such that that detector was the only one to detect the photons. There are also configurations where no detector detected it. So, if in some configuration, a detector detects the photon, and goes to check on another detector, it will find that the other detector has not detected the photon, not because some instantaneous space spanning signal collapsed the wave function, but because in that configuration the photon did not go that way.
I see, so the photon left the source as a particle and the wave picture represents the idea that the particle could have been anywhere, until you know which world you’re in.
But the mechanical-model-that-made-me-so-happy was that the photon was actually just the electromagnetic field trying to update. The electromagnetic field would have to update isotropically … it couldn’t just update along the route to a given detector.
Well, there is a similar mechanical model to the evolution of the Schrodinger wave function, which is to particles (including photons) as the electric and magnetic fields are to light in the classical model. This wave function is fundamental, the particles, and the configurations, or “worlds” are derived consequences.
Many Worlds made sense to me as a solution when I considered the case of an apparently random choice. Instead of the world collapsing on an arbitrary choice, each world gets one choice. In the case of interaction with a propagating wave of light, though, I don’t see how it would work. Perhaps something is incorrect with my fledgling model of light.
Let’s consider a single photon. That would still propagate as a spherical wave from the source. The wave expands uniformly from the source and I suppose that according to a classical theory (?), that wave could be perceived simultaneously by different people in different places around the source. Even if I interact with the wave by moving an electron that approximately cancels that wave, then my cancellation would propagate only at the speed of light, not instantaneously.
So how would Many Worlds work in this case?
That is indeed what the classical theory says. It is wrong. This is where the assumption that domain of the amplitude is continuous is a bad approximation.
Quantum amplitude flows into separate configurations. For each detector, there is a configuration such that that detector was the only one to detect the photons. There are also configurations where no detector detected it. So, if in some configuration, a detector detects the photon, and goes to check on another detector, it will find that the other detector has not detected the photon, not because some instantaneous space spanning signal collapsed the wave function, but because in that configuration the photon did not go that way.
I see, so the photon left the source as a particle and the wave picture represents the idea that the particle could have been anywhere, until you know which world you’re in.
But the mechanical-model-that-made-me-so-happy was that the photon was actually just the electromagnetic field trying to update. The electromagnetic field would have to update isotropically … it couldn’t just update along the route to a given detector.
Well, there is a similar mechanical model to the evolution of the Schrodinger wave function, which is to particles (including photons) as the electric and magnetic fields are to light in the classical model. This wave function is fundamental, the particles, and the configurations, or “worlds” are derived consequences.