NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/sci/physics/21720

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From: [e-mail] (Jack Sarfatti)
Subject: Peer review of Budnik's "delays" in Aspect's test of Bell.
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Date: Thu, 24 Dec 1992 06:56:06 GMT
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Sarfatti responds to:
*...* enclose my comments on Budnik
From: [e-mail] (Paul Budnik)
Subject: Re: PS on Budnik's "delay" in Bell's inequality test.
Date: 23 Dec 92 16:11:48 GMT

In article <[e-mail]>,
[e-mail].c
om (Bronis Vidugiris) writes:
> In article <[e-mail]> [e-mail] (Jack
Sarfatti) writes:

> I looked again trying to understand what is exciting Budnik so much. Does
he not know that Aspect's experiment in 1982 has polarization orientation
switching times that were short compared to photon flight times from source
to detectors. So that the nonlocal correlation of (cos@)^2/2 that violates
Bell's locality inequality is definitely observed across spacelike
intervals.

This is not correct.

*Paul, I'm sure Alain Aspect would not agree with you! Aspect stayed with
me in San Francisco a few years ago. He said all his attempts to think of
how to communicate on the connection failed because of unitarity - it is
significant that he did try! No doubt our Dostoyevskian Grand Inquisitor
Senor Baez and his fellow Friars would label him a "crackpot" for daring to
think such heresy!*

There was no *direct* measurement in Aspect's experiment of the delay
between when a particle traversed the polarizer and was detected.


*OK, Paul, now at least I am beginning to see what the hell you are talking
about in "delays" - you were not very clear before and I am not the only
one you confused. Let's try to picture your above remark in terms of a
spacetime diagram. Your key phrase is:

"the delay between when a particle traversed the polarizer and was
detected"

In my analysis this delay is negligible (i.e. short compared to flight
times from source to polarizer) and essentially irrelevant. Why do you
think it important?

                   4                                           5
                    \                                        /
                      \                                    /
                        \ 2                            3 /
                          \                            /
                            \                        /
                              \                    /
                                \                /
                                  \ a        b /
                                    \        /
                                      \    /
                                        \/
                                         1

1 = pair source emission event
2(3) = scattering of photon a(b) from polarizer A(B)
4(5) = irreversible absorption of scattered photon a(b) by detectors A'(B')

So Budnik's delays are 24 and 35 for photon pair a,b emitted from event 1.
For simplicity make everything symmetrical on each side. Suppose only one
photon pair through the system during a measurement.   Now suppose each
photon wave packet has time width T1. Let's also suppose that the time of
flight of a surface of constant phase of the photon probability wave
through the thickness of each polarizer is T2. Suppose the polarizer is
rotating at angular rare w. Suppose T1<<T2, then the angular uncertainty
d@(2(3)) is wT2. In the other extreme, if T1>>T2 the angular uncertainty is
wT1. Good measurements require that the angular uncertainty be small

d@(2(3)) << @(2,3)

compared to angle @(2,3) defined as the nonlocal parameter

@(2,3) = @(2) - @(3)

the space-time interval 23 is spacelike in Aspect's experiment because of
the fast acoustic switches (the switching times in @(2(3)) are short
comapred to 12(3).  In fact the ideal correlation of sqm of
(cos(@(2,3))^2/2 is independent of 23 frame invariant metric distance. What
possible relevance can 24 or 35 have to the basic idea of Aspect's
experiment? So far, Budnik I fail to see where the problem is. Perhaps,
someone else sees the problem?  Does anyone else see what Budnik sees? Well
let's continue.*


Aspect estimated delays based on assumptions about flight time.

*What does this mean? Anyone else understand what this means?*

Such assumptions

*What assumptions? State them!*

are not in general valid in QM.

You cannot know where a particle is at a given time unless you observe the
particle at that time.

*I agree with the above abstract remark but fail to see how it is relevant
to the concrete question at issue. Does any one else recognize how it is
relevant?*

See J. D. Franson, Physical Review D, pgs. 2529-2532, Vol. 31, No. 10, May
1985 for a detailed analysis of this issue.

*It would help if you could summarize what you understand Franson is doing
and show clearly how it relates to your idea which so far eludes me.*

If that is his concern then the answer is simple. But it seems to
be something else- he says the "delay" can be measured but he does not give
a clear and complete procedure so that I conclude it is much ado about
nothing. I would like to be proved wrong in this opinion if any one else
thinks they understand Budnik's idea.

The way you measure the delay is by varying the polarizers between states
that maximize and minimize the probability of joint detections.

*The probability of joint detection is (cos@)^2/2 so that @ = 0 is max and
@ = pi/2 is min. That much I understand. But I do not understand in
operational terms "measure the delay is by varying the polarizers between
states". Do you mean switching from 0 to pi/2 between arrivals of
successive photon pairs. Aspect certainly does the equivalent of that given
less than ideal conditions -but how does that relate to 24 and 35 in above
diagram which is a literal translation of your explicit statement?*

You then directly measure the time delays between when you have changed the
polarizers and when this affects the probability of a joint detection.

*This seems to be delusional word salad - totally meaningless in
operational terms. Now I may be being stupid here, but does anyone else see
what Budnik is driving at? What does it mean and how does it realte to his
earlier remark "There was no *direct* measurement in Aspect's experiment of
the delay between when a particle traversed the polarizer and was detected?
"


This is a technically more difficult experiment than Aspect's.

* Difficult indeed because it is apparently meaningless.*

Since you cannot control when a photon traverses the polarizer the delays
will be dominated by the lack of synchronization between when a photon is
emitted and when a polarizer changes state.

*This remark makes some sense, but it has no logical connection to "There
was no *direct* measurement in Aspect's experiment of the delay between
when a particle traversed the polarizer and was detected."

Although,"Since you cannot control when a photon traverses the polarizer
the delays will be dominated by the lack of synchronization between when a
photon is emitted and when a polarizer changes state."  makes some sense it
is wrong. First of all, a good experimenter will make sure that each
polarizer is steady when each photon wave-packet is scattering from it.
The wave packet widths are small compared to the distances 12 and 13 - and
the whole point of the coincidence circuitry is to make Budnik's point
wrong.*

You can minimize this by emitting photons at a rapid rate, but the rate
cannot be too high or you will not be able to distinguish joint detections
from the detection of two photons from different photon pairs. These
problems can be dealt with by increasing the total distance between the
photon source and detectors. This introduces additional technical problems.
I do not know how difficult such an experiment would be, but it is
certainly doable in theory. That is all this is needed to prove my claim
that quantum mechanics is an incomplete theory.

I'm curious too - I checked and I don't have ready access to the reference
> Paul cites and I haven't followed up 'special ordering' it from our
library. One concern I had in thinking back over the experiment was the
delay between the emission of the cascade photons.  [I assume Aspect used
cascade photons.]

Aspect measured the times between joint detections and depended on the
geometry of the experiment and the flight time of photons to estimate the
delays. Franson argued that this was not legitimate.

*Really, then give relevant quotes by Franson.

The delays could have been as long as the excited states of the atom
emitting the photon or even as long as the coherence times of the lasers
used to excite the atoms.

*Surely, both these obvious delays were well understood by Aspect and taken
into account by him. The main reason its so hard to understand what you are
babbling about is that you keep pulling the rug out from under us in the
meaning of "delays" How do the "delays" of the above paragraph square with
the meaning of "delays" in ""the delay between when a particle traversed
the polarizer and was detected"? Budnik is, by implication attacking
Aspect's competence. It would be good for Aspect to respond to Budnik.
Like Pontius Pilate I wash my hands of this and ask "What is truth?" I have
not changed my opinion that Budnik has no real physics here - my verdict is
"BOGUS!" - to the cross!*