On 21/04/2016 1:34 am, Jesse Mazer wrote:
On Tue, Apr 19, 2016 at 8:54 PM, Bruce Kellett
<[email protected] <mailto:[email protected]>> wrote:
So, the fact that these simulated results were supposed to have
come from an entangled singlet pair has not been used anywhere in
your simulation. It has only ever been used to link the copies of
Alice and Bob, the statistics that they observe come entirely from
what you happen to put in you accumulator for each setting of the
relative orientations.
Saying the idea of a singlet pair "has not been used anywhere in your
simulation" and then saying it has "been used to link the copies of
Alice and Bob" seems like a contradiction--isn't the linking itself
part of the simulation?
No, there is no contradiction. You have used the fact that they are
measuring parts of an entangled system only to link the sets of results.
Nowhere have you used the quantum properties of the entangled singlet
pair in the simulation to calculate the probabilities: you have imposed
those probabilities from outside by fiat. One might have well have used
times read on synchronized clocks to link the experiments -- just as I
used the fact of writing on a single token to show that the results were
part of the same experiment.
After all, getting a message from Bob is part of the simulated world
that Alice experiences, just as much as her own measurement. What we
have here is just a single distributed simulation being run on
multiple computers computing different parts of it in parallel, and
communicating data in order to determine interactions between those
parts. Any local physics model can be simulated in such a way,
including ones that don't involve "copies" existing in parallel in a
given region--for example, space can be divided into a cubic grid and
each computer can compute the internal dynamics in each cube, and
computers that simulate cubes that share a face in common can share
there data so that particles or waves leaving one cube through a given
face will appear in the neighboring cube from the same face. This
would still be one big simulation, just computed in a distributed way.
And the fact that you *can* distribute the computation of the whole
universe into a bunch of local sub-simulations that communicate only
with their neighbors is true if and only if the laws of physics
governing your universe are "local" ones.
I agree that you can generate the required statistics locally in
this way. In fact, I can do it even more simply by taking a number
of urns and labelling each with a particular relative orientation,
say parallel, antiparallel, 90 degrees, and so on. In the
"parallel" urn I place a number of tokens labeled (A+B-) and an
equal number labelled (A-B+). In the "antiparallel" urn, I place a
number of tokens labelled (A+B+), and an equal number labelled
(A-B-). In the "90 degree" urn I place a number of tokens labelled
(A+B+), an equal number labelled (A+B-), an equal number labelled
(A-B+), and finally an equal number labelled (A-B-).
I don't see how your method would be a *local* simulation though. In
order for it to be local, you'd need to set things up so Alice first
picks her result from one of three urns at her location, and Bob first
picks his result from one of three urns at his location, and they can
see the result of their own pick before either one knows which urn the
other one picked from.
No, I am simulating the system as it stands after Alice and Bob have
communicated, written their results on the tokens, and put them in the
appropriate urns. All completely local. The point is that then a third
party can come along and discover the statistics of their results by
pulling sequences of tokens, at random, from the urn relating to the
relative orientation of interest. The non-locality comes from the fact
that the quantum singlet state gives a non-local connection between A
and B in order that that their actual results can give the same
statistics as the ones I generated by hand above. The actual quantum
calculation of the probabilities is explicitly non-local. You have,
somehow, to find an alternative way of generating these statistics. And
that you have not done.
Since you are accumulating joint results according to the statistics
that you have calculated on the basis of standard quantum mechanics,
completely independently of the properties of the actual singlets states
that Alice and Bob measure, my example is exactly equivalent to yours.
But that is precisely what you toy model does. It has absolutely
no connection with EPR or real experiments. One could generate any
arbitrary set of statistics to satisfy any theory whatsoever by
this method. You have demonstrated absolutely nothing about the
locality or otherwise of EPR.
Would you agree that in my toy model the results at each location can
be generated in realtime (each experimenter finds out their own result
before finding out the other one's result, and before they have any
way of knowing what detector setting the other one used), and in a
local way (the rule that generates a result that appears at a
particular position and time doesn't depend on anything outside the
past light cone of that event), and that the subjective probabilities
for each experimenter match those of the EPR experiment?
No, I don't agree with this. You have not used the quantum properties of
the singlet state in your simulation, so there is no way that you can
reproduce the quantum probabilities. All you can get is repetitions of
the four possibilities (++), (+-), (-+), (--), with equal probabilities.
You have set things so that A and B are independent, which is equivalent
to having them measure independent unpolarized particles, not members of
an entangled pair.
If you agree but think your urn model is doing the same, please
explain it in more detail because as I said, your short description
above doesn't seem to me to have these characteristics.
No, my urn model was not intended to model an EPR experiment -- it was
meant to be equivalent to your simulation which, I maintain, does not
model the EPR situation either.
Bruce
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