On Sunday, October 6, 2019 at 3:46:19 PM UTC-5, Brent wrote: > > > > On 10/6/2019 4:33 AM, Philip Thrift wrote: > > > > On Sunday, October 6, 2019 at 6:03:29 AM UTC-5, Bruce wrote: >> >> On Sun, Oct 6, 2019 at 7:23 PM Bruno Marchal <mar...@ulb.ac.be> wrote: >> >>> When Alice and Bob are separated, and measure their particles state, the >>> MWI only ask that whatever they found will be correlated. In the world >>> where Alice finds “up", Bob will find "down", and in the world where Alice >>> finds “down”Bob will find “up”. But without any FTL action at a distance. >>> >>> >> OK. So what is the explanation for this aspect of MWI? I am asking for a >> local causal physical explanation for the observed facts. Nothing else will >> suffice at this point. >> >> >> Aspect took a long amount of work to ensure that light has not the time >>> to bring the correlation, and as the choice of “Alice”’s direction of spin >>> measurement is arbitrary, unless you bring t’Hooft super determinism, the >>> influence has to be FTL. Not so in the MWI. >>> >> >> The influence is non-local, that does not imply FTL. If there is no >> non-local influence in MWI, how is the observed correlation formed? Just >> answer the question. >> >> >> Well, I have looked at your "explanations", and at a lot of other MWI >>> so-called explanations, and not one of them has been satisfactory. These >>> "explanations" are either hopelessly vague, or they misunderstand what is >>> required, or, like Wallace, they simply wimp out of any explanation at all. >>> If you can do better, then do it. But despite years of asking, you still >>> have not come up with any credible explanation. >>> >>> >>> It is the same as the one in Price FAQ, or in Tipler’s paper, and it is >>> coherent with Deutsch-Hayden one, if recatsed in a many histories approach. >>> >> >> And I have, on many occasions, shown that these approaches are not >> successful in eliminating the non-locality. Price and Tipler, indeed, just >> reproduce the standard non-local quantum account. If you are so convinced >> that these papers give a fully local explanation for the violation of the >> Bell inequalities, then reproduce the argument here so that we can agree on >> what, exactly, we are talking about. >> >> Bruce >> > > > > EPR and Many Worlds has been "worked out" many rimes before, but hasn't > really changed the world. > > http://settheory.net/many-worlds > > The idea is to dismiss the reality of the collapse, consider that the > deterministic evolution without collapse is all what happens, and admit a > persisting coexistence of all possibilities in parallel worlds, in each of > which things would only "look as if" the collapse happened. > > *The Many-worlds interpretation of the EPR paradox* > > Imagine a pair of entangled particles, that will be simultaneously > measured, each in a specific way, by Alice and Bob, such that for each, the > probability is 1/2 to find heads or tails, but globally there is only 10% > probability that they get the same result. > > So, Alice seeing her measurement result evolves into a superposition (or > split) between 2 mental states : Alice-head and Alice-tail, with the same > weight of 1/2 each. > > In the same way, Bob evolves into a superposition (or splits) into 2 > copies : Bob-head and Bob-tail, each with weight 1/2. > > > "Evolves into" is just MWI-speak for wf collapse into separate worlds. > This doesn't solve the problem of why Alice and Bob's worlds are correlated. > > Then, Alice and Bob meet again. > > Alice-head sees Bob in a superposition of states, composed of 10% of > Bob-head and 90% of Bob-tail, > Alice-tail sees Bob in its remaining states, that is a combination of 90% > of Bob-head with 10% of Bob-tail. > Bob-head sees Alice as in a superposition of states, composed of 10% of > Alice-head and 90% of Alice-tail > Bob-tail sees Alice in a combination of 90% of Alice-head with 10% of > Alice-tail. > > > But that's the problem. How do they come to have these combinations > instead of 50/50. If you suppose it's something about the wf, then it's > non-local because the wf is non-local. If you suppose it's something that > happens because of the interaction between the "worlds" then that something > was determined non-locally in the setup using correlated particles. > > Brent > > > Then, Alice tells Bob her measurement result. > For her this changes essentially nothing : > When Alice-head says "head" she sees Bob as deterministically evolving > from the mixture (10% of Bob-head + 90% of Bob-tail), into the mixture (10% > of Bob-head-head + 90% of Bob-tail-head) ; and similarly for Alice-tail who > says "Tail". > > But bob's experience here is a bit different : > Bob-head sees Alice's state collapsing from the undetermined state of (10% > Alice-head + 90% Alice-tail), into either Alice-head (with 10% probability) > or Alice-tail (with 90% probability); this splits himself between > Bob-head-head and Bob-head-tail with these probabilities. > Meanwhile, Bob-tail sees Alice's state collapsing from the undetermined > state of (90% Alice-head + 10% Alice-tail) as he saw her, into either > Alice-head (with 90% probability) or Alice-tail (with 10% probability). > > > > and > > *Many Worlds Model resolving the Einstein Podolsky Rosen* > *paradox via a Direct Realism to Modal Realism Transition that* > *preserves Einstein Locality * > https://arxiv.org/pdf/1108.1674.pdf > > > And the "reverse" of many worlds (sum-over-histories): > > https://www.perimeterinstitute.ca/personal/rsorkin/some.papers/63.eprb.pdf > > @philipthrift > > > Still, histories vs. worlds works better:
Finally, we would like to return to the question of locality by commenting briefly on the sense in which this fundamental feature can be regarded as present in the sum over histories formulation we have been using. It is true, of course, that no blatantly nonlocal process like wave-function collapse enters this formulation, but on the other hand the essential quantity on which the whole framework rests — the probability amplitude — already has a global character since it pertains to entire (one-way or two-way) histories, which are spread out not only in space but in time as well. In such a framework it is not even clear a priori that anti-causal effects are excluded, let alone non-local ones (in the absence of Lorentz invariance, the two are not necessarily connected, of course.) If nonetheless, neither sort of effect is present, it can only be because the amplitudes take a special form, to wit that the amplitude of an entire history is the product of the amplitudes of its spacetime parts. @philipthfit -- 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/cd678dec-0c40-4fdf-b764-d52f5ab04c81%40googlegroups.com.
