On Friday, November 17, 2017 at 3:18:39 PM UTC-7, Bruce wrote: > > On 18/11/2017 12:10 am, Bruno Marchal wrote: > > On 15 Nov 2017, at 22:26, Bruce Kellett wrote: > > On 16/11/2017 1:55 am, Bruno Marchal wrote: > > On 15 Nov 2017, at 00:55, Bruce Kellett wrote: > > On 15/11/2017 12:47 am, Stathis Papaioannou wrote: > > On Mon, 13 Nov 2017 at 8:54 am, Bruce Kellett <bhke...@optusnet.com.au > <javascript:>> wrote: > >> >> I don't think you have fully understood the scenario I have outlined. >> There is no collapse, many worlds is assumed throughout. Alice splits >> according to her measurement result. Both copies of Alice go to meet >> Bob, carrying the other particle of the original pair. Since they both >> have now met Bob, the split that Alice occasioned has now spread to >> entangle Bob as well as the rest of her environment. So there are now >> two worlds, each of which has a copy of Bob, and an Alice, who has a >> particular result. Locality says that Bob's particle is unchanged from >> production, so when he measure its spin, he splits into two copies, >> according to spin up or spin down. Since Alice is standing beside him, >> she also becomes entangled with his result. But Alice already has a >> definite result in each branch, so we now have four branches: with >> results 'up-up', 'up-down', 'down-up', and 'down-down'. However, only >> the 'up-down' and 'down-up' branches conserve angular momentum. How do >> you rule out the other branches? > > > When you put something in the cupboard and come back later to get it, why, > under MWI, is it still there? > > > I don't understand the significance of your question. Why wouldn't things > remain stable in MWI? After all, the whole world, as it is, becomes > entangled with the particular branching event. > > > OK, but not instantaneously. This might be the point where we disagree in > the interpretation of the Non-collapse theory. > > > I think that the general idea is that the entanglement with the result > spreads at the velocity of light -- inside the forward light cone. This > spread of entanglement does not require that all objects in the forward > light cone have explicitly interacted with the original event. The > mathematics are quite clear on this point. > > > You are right. So you might need an experience like Mandel & Co(I will > look at the reference, I guess you see which experience I allude to) where > two distant lasers create a singlet state non locally. That one has made me > doubt that MW could avoid Action-at-a-distance, and some thought experience > by Lucien Hardy too, but eventually, I remain unconvinced, > > > You will have to give more precise references. Searching on these names > throws up so many papers that it is impossible to sort out exactly what you > mean here. > > because wherever are the actors, the singlet state never describes a > non-local affair, it only predicts the result of the people who will met at > some time. > > > The singlet state is intrinsically non-local. >
But as Brent claims, and I think he is correct, there is a basis in which the singlet state is a eigenfunction. In that basis, the obvious non locality may not be so obvious, if indeed it exists. AG > It actually has nothing to do with whether people meet or not - it > describes a situation which explicitly violates Einstein's notion of local > realism: the state of one of the entangled pair is not separable from the > state of the other distant particle. Non-separability here implies > non-local influence, or simple non-locality. The attempt to claim that > non-separability does not imply non-locality is mere verbal gymnastics, > with no physical content. > > Bruce > > -- 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.
