On Wed, Nov 27, 2024 at 2:21 PM smitra <[email protected]> wrote: > On 26-11-2024 23:27, Bruce Kellett wrote: > > > You are talking a lot of nonsense. I refer you to a paper by Brunner > > _et al._, Rev Mod. Phys. 86 (2014) pp.419-478. > > This is also available at arxiv.org/abs/1303.2849 [1] > > The abstract states "Bell's 1964 theorem, which states that the > > predictions of quantum theory cannot be accounted for by any local > > theory, represents one of the most profound developments in the > > foundations of physics." > > Brunner _et al._ go on to derive the CHSH (Clauer-Horne-Shimony-Holt) > > inequality using only local dynamics, and prove that this inequality > > is violated in conventional QM, as well as in many experiments. This > > proves that quantum mechanics is intrinsically nonlocal. (If you like, > > it demonstrates that nonlocal states are intrinsic to the theory.) >
> > > >> And b.t.w. if there is a Bell's theorem purely about unitary QM that > >> doesn't invoke hidden variables, you could just state it right here. > > > > I don't prove Bell's theorem here, but I have referred you to Bell's > > original papers, and also to the review article by Brunner et al., > > above. If you actually do the research for yourself, you can see that > > many authors agree with what I have been saying. You are the one that > > is out on a limb. > > > > > > I have given you references here, and I have referred you to Bell's > > original papers before.. But you do talk an awful lot of nonsense. > > > > Quote from Brunner's paper: > > > "To avoid any misunderstanding from the start, by “locality” we > do not mean the notion used within quantum mechanics and > quantum field theory that operators defined in spacelike separated > regions commute. Bell’s notion of locality is different and > is clarified below" > They define locality in terms of factorizability, as in their equation 3. > And if I read on to see what Bell’s notion of locality is, then, as > expected, it involves local hidden variables. > > "Let us formalize the idea of a local theory more precisely. > The assumption of locality implies that we should > be able to identify a set of past factors, described by > some variables λ, having a joint causal influence on both > outcomes, and which fully account for the dependence > between a and b. Once all such factors have been taken > into account, the residual indeterminacies about the outcomes > must now be decoupled, that is, the probabilities > for a and b should factorize:" > > So, basically the standard local hidden variables framework. > Read a little more carefully. "Once all such factors have been taken into account .... the probabilities for a and b should factorize." If it were a hidden variable theory, then the probabilities for a and b would depend on those hidden variables, and that is what is explicitly ruled out. So Brunner is not using a hidden variable theory. The main point is that, even taking unknown joint causal factors into account, the probabilities at the remote ends factorize. In other words, what happens at A does not affect what happens at B, and vice versa. This is the notion of locality that they use to derive the CHSH inequality -- nothing to do with hidden variables. 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 [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAFxXSLQaeuCzqamCZHnZ7JvVJnJ4izB3LMqN-i4D1ytpMaKerQ%40mail.gmail.com.
