On Sunday, October 6, 2019 at 7:01:33 AM UTC-5, Bruce wrote: > > On Sun, Oct 6, 2019 at 10:33 PM Philip Thrift <[email protected] > <javascript:>> wrote: > >> On Sunday, October 6, 2019 at 6:03:29 AM UTC-5, Bruce wrote: >>> >>> >>> 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. >> 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. >> > > All very well, but what is the mechanism for this to happen -- what is the > joint wave function when they meet that has these weights for the relevant > branches? How does unitary evolution from the initial state lead to this > particular wave function with these probabilities? And what determines the > probabilities? > > There is no actual causal explanation here. > > >> 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. >> >> 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". >> > > Interesting. What is the interaction that occurs when Alice says "head" > that causes Bob to deterministically evolve in this way? > > >> 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. >> > > So there is a collapse after all? > > >> 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). >> > > There is no dynamics for this in the Schrodinger equation. Since there is > no interaction at the intersection of the forward light cones (it is not > necessary for Alice and Bob to actually meet; we could have a third party > collect the data), the probabilities for the four possible worlds have to > have been set while Alice and Bob were still at space-like separations -- > in other words, at the time of their individual measurements. Or else there > is no explanation for the 10% and 90% probabilities mentioned in this > account. > > Bruce >
This (I looked up) came from this dude's site: http://spoirier.lautre.net/en/ Happy reading. How does Sean cover EPR in his book? Everyone has a story to tell. @philipthrift -- 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/6001096e-4548-45bb-a19a-4c94a357dcbf%40googlegroups.com.
