On Tue, Apr 5, 2022 at 7:16 AM smitra <smi...@zonnet.nl> wrote:
> On 04-04-2022 01:38, Bruce Kellett wrote:
> > On Mon, Apr 4, 2022 at 12:52 AM smitra <smi...@zonnet.nl> wrote:
> >
> >> MWI is deterministic, but it's not a hidden variable theory. Bell's
> >> theorem is proved by assuming you have local hidden variables that
> >> specify the outcomes of experiments and then deriving inequalities
> >> that
> >> certain correlations should satisfy.
> >
> > The central assumption that Bell makes is that of locality, or
> > separability. He shows that any local (separable) theory must give
> > correlations that satisfy the inequalities. Whereas QM, and
> > experiment, show that these inequalities are violated.
> >
>
> Determinism is also assumed
It is not. Bell made no such assumption. I require textual proof of such a
claim.
> QM is not deterministic. And locality is
> not the same as separability.
>
It is. You show me a separable system that is not local, or a local system
that is not separable.
Humean supervenience, which regards all of physics as supervening on
isolated local point-like objects, is local by construction. It has no
non-separable states by definition. The argument is simple:
All local states are separable (By definition of locality and
separability).
Therefore non-separable states are not local. (Modus tollens)
Quantum mechanics embodies non-separable states.
Therefore quantum mechanics contains non-local states.
>> QM violates the Bell inequalities,
> >> which means that there cannot be an underlying local hidden variable
> >> model for QM. But QM itself can be local,
> >
> > That is not a valid conclusion. Any local account of the correlations
> > can always be cast as a hidden variable theory -- if for no other
> > reason than if there is a local mechanism at play, this mechanism is
> > not evident in the standard theory (therefore hidden). Everettian many
> > worlds, if they could actually play this role, would be counted as
> > hidden variables for Bell's analysis. Bell does not specify what form
> > these hidden variables should take.
>
> If all outcomes are realized then there cannot exist hidden variables.
>
That is a rather arbitrary assertion. And it is not true. Hidden variables
are variables or things that are not seen.
> The outcome of experiments is fundamentally stochastic in the MWI.
>
The outcome of experiments is stochastic in ordinary QM -- QM is not
deterministic.
>
> >> Bells's theorem does not
> >> address theories that are not local hidden variable theories.
> >>
> >> QM itself provides a local explanations for all experimental
> >> outcomes, including for the Bell correlations.
> >
> > Then give it!
>
>
> I'll write up the local account for a Bell-type experiment performed in
> a quantum computer.
>
I have seen attempts at such accounts. The trouble is that Aspect's
experiments were not performed in a quantum computer! It is Aspect's
experiments that are to be explained.
It would be more interesting if you could give such an account for a
classical computer. What is it that is significant about the QC? It is
generally understood that a quantum computer might give a speed-up on some
tasks, but it cannot actually do anything that a classical computer could
not do, given sufficient time.
The interesting question is why quantum computer accounts do not correspond
to laboratory experience. I think it has something to do with the
formation of permanent records. But you might have a better account.
Bruce
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