On 22-11-2024 05:45, Bruce Kellett wrote:
On Fri, Nov 22, 2024 at 3:23 PM smitra <[email protected]> wrote:
Bell's theorem says that no local deterministic hidden variable
theory
can explain the correlations that QM predicts. So, Bell's theorem
doesn't say anything about QM itself, it says something about hidden
variable theories that seek to explain the correlations observed in
QM
experiments. So, you modify QM and assume that QM is explained by a
classical deterministic hidden variable theory and then you obliged
to
take non-locality on board, or else your hidden variable theory will
fail to reproduce at least some of the correlations predicted by QM.
Nothing in here implies that QM is non-local.
The results of Bell's theorem imply exactly that. Bell assumes that
the theory is local, and shows that the QM results violate particular
inequalities. The theorem is NOT about non-local theories since Bell
does not assume a non-local theory.
Bell assumes a hidden variable theory and then shows that the hidden
variable theory must be non-local. So, it's about hidden variable
theories, not about QM. The relevance t QM is that it implies that
quantum mechanics cannot have an underlying local hidden variable
theory, not that QM itself is non-local.
Saibal
Everett introduces the splits as an effective description
appropriate
for describing macroscopic observers. He introduces density matrices
so
it should be clear that this isnt an exact qjuantum emchancial
description and it will certainly fail to correctly describe subtle
effects due to entanglement.
Density matrices are not an approximate form of QM.
There are no independent branches.
That is what decoherence is supposed to give you.
That is not the case. Everettian quantum mechanics says that they
both
split on to two branches, and there is no clear way in the
formalism
to see how the branches for the two individuals are related. In
any
model, in which both outcomes are necessarily realized for every
measurement, there is no way to relate the outcomes.
Everettian QM says that this is what effectively happens, but it's
obviously not an exact description and will fail to take into
account
subtle effects due to entanglement.
In other words, Everettian QM, or many-worlds, is not able to give an
account of the correlations. You are saying that that is because it is
not an exact theory. This is a pretty extreme way of getting out of
the difficulty that I have pointed out. If Everett is not just a
version of exact QM, it is of no use for anything. My claim is that it
cannot reproduce the observed correlations, therefore it is not a
version of standard QM, and is of no use for anything.
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/CAFxXSLQMRcefzw1Jfb6VCrkDeaVWZHAtK09BCe_-b%3D9Ho%3DiyFQ%40mail.gmail.com
[1].
Links:
------
[1]
https://groups.google.com/d/msgid/everything-list/CAFxXSLQMRcefzw1Jfb6VCrkDeaVWZHAtK09BCe_-b%3D9Ho%3DiyFQ%40mail.gmail.com?utm_medium=email&utm_source=footer
--
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/035e761427325a9e54f4a5707904eb36%40zonnet.nl.
