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wm

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__Preamble__: I have yet to find a reason to abandon my support of a LOCAL interpretation of QM; especially in relation to EPRB. It is therefore my hope that we might here bring the issue to a head. Given the frequent verbal misunderstandings across the LOCAL--NONLOCAL divide, it is also my hope that we might resolve the issue in the beautiful (and usually clearer) language and logic of mathematics.

PS: I suggest we constrain our discussion on this thread to the EPR-Bohm experiment with spin-half particles; it being the source of Bell's (1964) theorem. So:

On another thread, I (

**wm**) wrote:

wm said:Dearvanesch, I appreciate your defence of MWI but it still does not make sense to me (though I am a hardened LOCALIST):

1. You say:such as non-conspiracy in nature which requires random events to be statistically independent if there is no causal link somewhere, in one way or another.

I thought that the experimental results reveal statistical (= LOGICAL) dependence? Which is what I would expect, given that the ''entangled particles'' (created by the conservation of angular momentum) represent some of the highest correlations that we can generate (ie, the particle-state is spherically symmetric). Given then that the measuring-devices are also HIGHLY correlated by their differential setting: the detected correlations appear to be LOCAL and non-mysterious to me. What am I missing?

2. To help my understanding of MWI: Let us say that I come to Paris (to discuss MWI with you) and we agree to toss a coin to decide who pays for dinner. As the coin arcs through the air, I guess we agree that it is in a superposition? On coming to rest, thecoin reveals a definite result.

It seems to me that you and I remain physically in the world with the definitive physical result (the world where we expect to have dinner): AND that no other real world exists. Why then the need for MW in MWI?

Thanks,wm

**DrChinese**replied:

(Emphasis added.)DrChinese said:The measuring devices in Bell tests are sometimes set while the entangled particles are mid-flight. Therefore their settings cannot becausally correlated.

The mystery is this: was theoutcome of a particular detector setting determined when the particle pair was created? If you say YES, then you run afoul of Bell: because then the particles must be carrying enough "answers" to match all possible detector settings (Bell shows this cannot be true). If you say NO, thenhow does the answer at one point get transmitted to the other point?

1.

__Causally correlated__?? DrC, note that I said that the detector settings are correlated by their diifferential setting. If detector A on the left is set at

**a**(a unit vector) and detector B' on the right is set at

**b'**(another unit vector), then the detector settings are correlated by a function of (

**a**,

**b'**): that is, by a function of the differential setting.

For example: If we took cos(

**a**,

**b'**) as the correlation function; +1 indicates a parallel setting; -1 indicates an antiparallel correlation; etc.

Of course the correlation that counts is that established by the respective detector-settings at the instant of arrival of each particle:

__set in any manner of your choosing__.

2. Was the

__outcome of a particular detector setting determined when the particle pair was created__?? The outcome was determined when the particle and the detector interacted LOCALLY.

So could I ask you to provide the detailed maths by which you derive the EPRB correlation function? So that I might see where you believe that nonlocality enters (in the language of maths.)?

3.

__How does the answer at one point get transmitted to the other point__? ??

Well, in that we have not introduced Alice and Bob to the discussion thus far:

__it does not get transmitted__! How could it?

Trust this all helps to convince you of the need for your mathematical derivation of the EPRB correlation function,

With best regards,

**wm**

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