> On 3 Oct 2019, at 13:31, Bruce Kellett <[email protected]> wrote: > > On Thu, Oct 3, 2019 at 7:08 PM Bruno Marchal <[email protected] > <mailto:[email protected]>> wrote: > > On 1 Oct 2019, at 19:37, 'Brent Meeker' via Everything List > > <[email protected] > > <mailto:[email protected]>> wrote: > > On 10/1/2019 4:38 AM, Bruno Marchal wrote: > >> Right. Then the non locality has disappeared from the wave equation at the > >> start. > > > > No, Bruce's point is that it must be present at the start. Otherwise Bell's > > inequality couldn't be violated. > > Bruce agree that there is no FTL action, that is locality. The non locality > is in the perspective view. It is not a global truth, as that is obvious if > you agree that the wave function evolution is only a rotation in some space. > Rotation are typically local, even in abstract spaces (which in Everett and > with mechanism are the real thing). > Now, with “one physical universe”, that non-local perspective implies some > FTL action. > > I think you have missed the point, Bruno. The wave function itself is > non-local.
I certainly missed the point! I cannot make much sense of the sentence "The wave function itself is non-local”. > Consider the entangled singlet state that we have been talking about: > > |psi> = (|+>|-> - |->|+>)/sqrt(2). > > The kets in the tensor product refer to different particles, with arbitrary > separation in space-time. But this is a single state. Because it is > non-separable, and refers to different spacetime locations, it is > intrinsically non-local. You can rotate it as much as you like in Hilbert > space, but you will never remove the non-locality. That is the way it is -- > it will always refer inevitably to two separate spacetime locations. We do interpret the state very differently. I have no problem with labelling such a state “non-local”, but I interpret it as a set of universe where the particles are correlated, in all direction. If some bob and Alice share such state by accompanying each particles, they will always agreed on the correlation *with the Alice and Bob of their own universes*. But as long as they have no make a measurement, they are in all correlated-particles. If Alice makes a measurement and find “up”, she knows that the only Bob she has access to will have found “down”. If Bob makes a measurement and find “up”, he knows that the only Alice he has access to will have found “down”. And this in all directions, and when Alice and Bob makes their measurement they just see in which branches they are on a continuum of all possible spins. In this way, no FTL influence, and we have the inseparability,or non-locality. > > As Wallace reports Deutsch to have said: "quantum theory is a theory of local > interactions with non-local states I can agree with this. But such non-locality implies FTL influence (even if without any signalling possible) in any unique universe picture. > ." So with EPR correlations, the state is intrinsically non-loca And I am OK with this. > l but all the measurement interactions are local. OK. > The trouble is that, because of Bell's theorem, there is no local causal > explanation of the correlations — In one universe? That would implies FTL influences. But in the MW, we keep that non local fateure of the wave, but get an interpretation where we see that neither Bob nor Alice influence each other particles at a distance. They will each meet the relevant corresponding Bob and lice in their histories. The wave is the map of their accessible histories among a continuum (or bigger). > they are evidence of the non-locality of the state. No problem with this, and that is why I said that if Aspect confirms QM and the violation of BI, I would take it as a confirmation of the existence of the parallel histories, but I might be biased as this confirms what O predicted from simple arithmetic +.Mechanism. > And there is no FTL action -- that would be a local hidden variable causal > explanation, and Bell rules that out. This I do not understand, unless you bring t’Hooft super-determinism. In a unique universe, the violation of BI requires that when Alice do a measurement she influences and change the “map of the accessible reality” of Bob. They still cannot do signalling, but, with or without hidden variables, Alice does restrict instantaneously the state available Bob. Withe MW, as long as the light has not entangle Bob, Bob can make a measurement entangling him so other Alice of the multiverse. Everyone will agree with what the singlet state predicts, and no FTL signalling, nor influence has to occur. The world/reality/histories/computation-seen-from-the-multiplying-subject differentiate as decoherence speed, which is alway slower than light. Bruno > > 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 [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLSewE7FaznrJTY6OeQO240hqKX4DSm6rW1743PGfUQc%3DA%40mail.gmail.com > > <https://groups.google.com/d/msgid/everything-list/CAFxXSLSewE7FaznrJTY6OeQO240hqKX4DSm6rW1743PGfUQc%3DA%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/32A902EE-B15F-45A7-858E-BA1005C66E17%40ulb.ac.be.
