Gordon Watson wrote:1. I use the term "pristine" to be clear about a key assumption: that the particles reach Alice and Bob in the same condition that they were in when they left the source.
That is fine, and I understand that. But "pristineness" is not a property of a particle. It is an adjective you use to describe a particle based on information you may have about the history of the particle. You may be in possession of complete information about the current state of a particle and still not be able to ascribe "pristineness" without information that is external to the particle at the moment. Such that different observers who may or may not have that external information may draw different conclusions about "pristineness". I'm not saying it is a useless concept. Rather, it is very useful. All I'm telling you is that you should let go of the idea that it is an "objective property" of the particle. It is not.
2. I concede no points by discussing particles and beams. An unpolarised beam might be built from unpolarised particles or particles of varied polarisations.
So then tell me what you mean by an "each particle ... IS unpolarised". The last time I asked, you started talking about beams. The question is about "each particle". Why do you find the need to bring beams into the discussion when explaining what you (or Bell) mean by "each particle ... IS unpolarised"?
3. What do you mean by "the polarisation of the source"? For example, in the decay of an excited calcium atom [the source] to produce a pairwise-correlated photon-pair.
I explained that pretty clearly I think. If a source produces particles such that their individual polarization vectors (or spin directions if you prefer) have a well defined relationship between them, then the source is polarized as far as it's production of particles is concerned. Any such beam of particles is a polarized beam. Examples of such "well defined relationship" include "linear polarization" and "circular polarization". If there is no well defined relationship, then the source is unpolarized and any such beam is unpolarized. Is there anyting in this description that is unclear?
4. As for my clarity: except for "unpolarised particles", I'm confident that you know the meanings of the terms that I use.
And that is the central point. You haven't been clear about that. In explaining Bell's contradiction, you said:
* PS: BUT see page 1, middle second paragraph: "preceded by filters that pass only particles of given polarisation, say those with spin projections +1/2 along z axis." That is odd wording imho; though I'm sure I know what he means: i.e., the particles are polarised by the filters such that those with spin projections +1/2 along z axis pass.
Now, I've explained to great detail why that explanation does not hold -- like "pristineness", it makes polarization out to be an epistemic property that only makes sense if you know that a particle passed through a filter. In other words, two particles that are exactly identical in all properties could have different "polarization" status if one passed though a filter and the other was "pristine". In such a case, polarization can't be a property of particles, since complete information about the current state of a particle will not allow you to ascribe polarization. Perhaps you should simply admit that Bell's use of "polarization" is inconsistent, or at least your characterization of it is?
Please derive the EPRB and the Aspect (2004) correlations with every pristine particle polarised.
PS: If that's not possible, what other factors are involved in your successful derivations?
WTF?! What has that got to do with this discussion? This is as far off to left field as me concluding this post by saying:
Therefore please prove Poincare's conjecture Please spell out your position in some detail; you know I'm the beginner here.
IMHO The point of this discussion in this thread is about the meaning of polarization as it relates to a single particle! What did you think the thread is about?