On Wed, Jun 14, 2017 at 5:01 AM, Bruno Marchal <marc...@ulb.ac.be> wrote:
> >> >> Even the 2-slit experiment will not produce interference if you remove >> the photographic plate and just allow the photons to continue into infinite >> space after they pass the slits because then the world splits but the two >> never recombine again so no interference. > > > > > This is a bit weird. I would say that the interference are still there, > but that we can't see them. > I don't see why you would say that. We know for a fact from experiment that you CAN place a detector next to one slit so you CAN know which slit the photon went through, but if you do that then the interference pattern disappears. How does the MWI explain that? It says that when the photon approaches the 2 slits the universe splits, but in one universe a record is made (in a computer or a paper notebook or a human memory) that the photon went through the left slot and in the other a record is made that the photon went through the right slot. When the photon hits the photographic plate it's destroyed but the 2 universes are still NOT identical because they have different records, so they never merge back together, there is nothing to interfere with, so nobody in either universe sees a interference pattern. It would work the same way if no record of which slots the photon went through was made but you removed the photographic plate (or brick wall) and so didn't destroy it and allowed the photon to continue on for eternity after they pass the slits. The photons will be on slightly different tracks for infinity and so the two universes will never merge together into one and so there is no interference between the two. > > > Without the photographic plate, we can still introduce a needle at a > position where no photon will ever go, > Not after the photon passes the slits you can't, you could never move your needle fast enough to get in front of it. And according to Quantum Mechanics there is no place you can say with certainty the photon will never go, but it can tell you that it is more likely to go some places than others. You could make a calculation beforehand and find a good point to place the needle and bet the photon will not hit it, in most universes you will win your bet but in some you will not. And one needle is not enough, to prove if interference did or did not occur, you'd need lots of photons and lots of needles, although a photographic plate would be much easier to use. > > > Interferences occur independently of our decision to observe them. > Yes, observation has nothing to do with it if the MWI is correct, however interference requires at least 2 things, and if nothing interferes with the universe no interference pattern will be produced; the 2 universes need to merge back together but that will never happen if they remain different (because a record of which slot the photon went through is different or because the path the photon is taking on its infinite voyage is different). John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
