On Tue, Mar 8, 2022 at 9:29 PM smitra <smi...@zonnet.nl> wrote: > On 07-03-2022 23:01, Bruce Kellett wrote: > > > > You have not demonstrated this -- you have merely assumed it. Zero out > > of ten for your explanatory effort. I am still waiting for someone who > > actually understands the problem to explain how MWI can give a local > > account of these correlations. > > > > Bruce > > The setting of the polarizers are also the result of only local > interactions. Processes in your brain determine how you will end up > choosing the setting of your polarizer. If the settings were not a > priori agreed (a set of different setting can be agreed a priori for a > Bell test), then that only makes the situation a bit more complex, you > end up in a superposition of different polarizer settings and in each > sector for a definite polarizer setting you are in a superposition of > the different spin outcomes. This extra layer of complexity does not > change anything. > > As far as the explanation of the correlation is concerned, this follows > the derivation of the correlations using quantum mechanics. For example, > for two spins in the singlet state one can take Alice's results of up > and down spins, represented by plus and minus 1's respectively, and > Bob's up and down results are assigned the opposite signs. Measurements > are done for an angle theta between the polarizers, the fraction of > differences in the string of ones and minus ones is evaluated. This is > repeated for an angle of 2*theta. Then for certain values of theta the > fraction of differences become more than twice as large when the angle > is doubled, this is inconsistent with local hidden variable theories due > to the fact that the differences can be interpreted as mutations in one > string and doubling the angle would then amount to adding the same > fraction of mutations twice over. The maximum fraction of mutations > would then be doubled if there is zero overlap, in case of an overlap > would be less than double. It's impossible to increase the fraction of > mutations by more than a factor of 2. > > While this then excludes a local hidden variable theory underlying > quantum mechanics, there is nothing nonlocal about quantum mechanics > itself. Every step is a local process here, from the choice to set the > polarizers, the creation of the entangled spin pairs, the measurement > process etc. etc. That the correlations one observes cannot be explained > by a local hidden variable theory, is a problem for such local hidden > variable theories. There isn't (for all we know now) a hidden variable > theory underlying quantum mechanics, nor is there anything in the > dynamics (except for objective collapse) that's inherently nonlocal. > > So, I don't see where the problem is. >

The problem is that you have not given a local explanation of the correlations. I agree that all local interactions are local. But there is a non-local effect arising from the non-separability of the entangled singlet state. You have not explained how this can be accounted for locally -- certainly not in the context of a many worlds, non-collapse, theory. MWI does not remove the inherent non-locality of the non-separable quantum state. 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLRNk56y8tdYm2%2ByfuapT0AS71F9hMSOCHr5iOqRkadKcA%40mail.gmail.com.