Re: I don't understand EPR

From: Oz (oz_at_farmeroz.port995.com)
Date: 07/27/04 

Date: 27 Jul 2004 13:50:50 -0400

Tom Trotter <tom129@juno.com> writes

>The paired photons produced by Aspect via
>atomic calcium cascades are moving in opposite
>directions, have different wavelengths, and
>opposite angular momenta. They're two different,
>and separate, 'particles'.

Oh. That makes it more complicated.
Much more.

>And, it's not necessary to be contemplating
>how they can be 'communicating' with each
>other. They aren't.

Good. Everyone else says they are....
Well, some do, anyway.

>The correlations in the combined context
>are due to the photons of any given
>pair being identically polarized via
>the emission process.

That seems simple enough, so why the fuss?

>The two photons
>need not be emitted in opposite directions,
>but if we select those that are, conservation
>of angular momentum now requires that their
>handedness be the same. Therefore, they must
>have the same polarization: both right- or
>both left-circularly polarized."

Ok, seems simple enough...

>Now, if you want to make a local hidden
>variable theory work wrt the combined
>context, then, as Bell noted, you'll need
>some sort of mechanism whereby the two
>ends of the experimental setup can
>instantaneously communicate. But, that
>would be a silly construction, since it's
>already been shown that lambda (the
>polarization of the photons) is irrelevant
>to the determination of coincidental
>detection.

I've lost it there.
As I read this its obvious.
It can't be obvious or there wouldn't be a fuss.

>In the individual measurement context,
>the emission-produced *polarization* of
>a photon is (along with the orientation
>of the polarizer that it is interacting
>with) the determining factor.
>
>In the combined measurement context, the
>emission-produced *relationship* between
>paired photons is (along with the combined
>orientations of the polarizers) the
>determining factor.
>
>In the combined context, since the
>*relationship* between paired photons
>doesn't vary from pair to pair (only
>the polarization does), the only variable
>left to consider in determining rates
>of coincidental detection is Theta, the
>angular difference in polarizer settings.
>
>Does any of this make sense,

Makes my head spin because it seems to say that the two particles are
emitted in a certain relationship. Say with parallel spin.

This means that if you detect one with a particular spin then you must
detect the other with that particular spin. That's because they always
had that spin from the start.

This doesn't gell terribly well though. If the particles are photons I
can rotate (one of) the polarisations by a stepwise path through a
series of polarisers. I was under the impression that if you did this
then you still maintained the parallel spin on final detection. There
are a variety of caveats one could bring to bear to overcome this, but I
am in fact unclear of the expected result.

I am also not 100% clear about spin, never having studied it.
I currently crudely classify it as I would polarisation, although I know
its a 3D thingy really.

>or do you
>think we should continue to talk about
>ftl or instantaneous communication between
>particles or filters and/or detectors in
>EPRBell experiments?

If you wouldn't mind, I would appreciate it. 

-- 
Oz
This post is worth absolutely nothing and is probably fallacious.
BTOPENWORLD address about to cease.      DEMON address no longer in use.
>>Use oz@farmeroz.port995.com<<
ozacoohdb@despammed.com still functions.

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