From: Paul.Budnik@mailbox.bison.mb.ca (Paul Budnik)
Newsgroups: sci.physics
Subject: Why do physicists make preposterous predictions?
Date: 25 Sep 92 01:57:17 GMT

Organization: Mountain Math Software, P. O. Box 2124, Saratoga. CA 95070

Look up at the sky this evening. Photons from stars and galaxies
as distant as millions and even billions of light years will strike
your eye. Many of these will, according to quantum mechanics, be in
a singlet state, paired with another photon. These two were created
in a single decay event and have been journeying through space in 
opposite directions for eons. Yet quantum mechanics maintains that
there are still connected. Put on a pair of polarizing sun glasses
(not ordinarily recommended for star gazing). Now as you turn your head
and change the angle of the polarizer you will instantaneously influence
all the singlet state photons that are paired with the ones
you are observing. This is true even though these paired photons may
be billions of light years distant. At least that's what quantum mechanics
implies.

Suppose there is an alien star gazer on a distant galaxy. By chance she
has on polarizing sunglasses and glances at a photon paired with one
you see. (An unlikely event, but this is a thought experiment.) The relative
angle of the polarizers of these two distant star gazers will affect
in an experimentally detectable way the probability that they will both
detect the two photons in a singlet state. This would not be surprising
if it were because of a polarization in the photons that was determined when
they separated in the distant past. However this is not the case. Quantum
mechanics predicts that the polarization for the singlet state
is determined at the instant one photon is observed. The correlation
function from quantum mechanics that predicts the probability of a joint
detection depends on the angle between the polarizers in a way
different from any function that assumes the photon polarization
angles were predetermined. The proof of this is known as Bell's theorem.
The results that quantum mechanics predicts are only possible if information
about the angle of at least one polarizer is transmitted
instantaneously across billions of light years to the other observation and
influences the results there. You cannot by changing the angle of your polarizer
send a signal to the distant star gazer. But you can, nontheless, change which
events are detected instantaneously over a distant of billions of light
years. At least thats the story quantum mechanics tells.

Why would serious physicists believe this seemingly preposterous prediction?
Surely there must be a vast body of experimental evidence that proves the
existence of such instantaneous action at a distance. Not exactly.

There have been several experiments. The most famous of which is Aspect's.
However Aspect did not directly measure the time between when a polarizer angle
changes and an affected photon is detected. Instead he estimated this
based on the time it would take a classical particle to traverse a polarizer
and be detected. Quantum mechanics makes it abundantly clear that we
cannot assume where a particle is between detections. If Aspect had reached
a conclusion conflicting with quantum mechanics but containing such a gross
error, his paper never would have made it past the referees. However, since
his results were consistent with quantum mechanics, it was widely hailed as
a decisive experiment. It took three years before Franson pointed out its
fatal flaw. It is still widely referenced as being decisive in spite of
this fatal flaw. There have been a several other experiments. None to
my knowledge, have addressed the fundamental issue in testing Bell's
inequality: proving that the detections and polarizer angles that affect
them have a space-like separation. In other words there is not shred of
experimental evidence to support this preposterous prediction.

Well then surely there must be some deep theoretical principle, thoroughly
proven in other ways, that is responsible for this prediction. Not exactly.

The theoretical principle on which this prediction is made is ... (sigh, I
cannot even give it a name without creating controversy). You see this
principle is so ill defined that it would be difficult to get two physicists
to agree on exactly what it is. Let us call it the observation principle.
It states that the wave function we use to make predictions is different
after an observation is made. Physicists cannot agree on whether the
wave function changes or we just select a different wave function that
was there all the time. But in any event we must change the model we
use to make predictions after an observation and this model changes
instantaneously when the observation is made throughout all space
that is relevant to an experiment. This raises some interresting questions
regarding special relativity on which there are about as many opinions as
there are physicists that have thought about these issues, but all
physicists agree on what the predictions are. They just have
no consistent theoretical basis for making them.

Well, if there is no experimental evidence in support of these preposterous
predictions and there is no well defined theoretical principle on which
they are based, then *surely* there is no way to change existing theory
so that all the thoroughly verified predictions of quantum mechanics are
intact but these preposterous ones are gone. Not exactly.

You see all it takes to build a theory consistent with all known experimental
results and free of the preposterous predictions is to say that the
wave function does not change instantaneously, but changes in a local
Lorentz invariant way just like every other known physical process.
This would imply that the singlet state would decay spontaneously into
independent quantum systems long before the particles are separated by
astronomical distances. The singlet state may not exist it all.
It may be an artifact of a quantum collapse process extended in
space in time that creates the two photons in the first place.

Well if there is absolutely no reasonable experimental or theoretical
foundation for these preposterous predictions why, in heaven's name,
do physicists make them?

I suggest two answers. This first is best understood through
the Hans Christian Anderson fairy tale *The Emperor's New Clothes*.

You see it was Einstein's (and his coauthors') paper, EPR, that started
the line of inquiry that ultimately led to Bell's result. Poor
befuddled Einstein thought there must be such a thing is objective
reality. He thought than quantum mechanics was an incomplete theory.
He really never understood `modern physics'. Unfortunately for it, the
non preposterous (local Lorentz invariant collapse) version of quantum
mechanics is an explicitly incomplete theory. It implies that the wave
function has an objective physical reality. No self respecting `modern'
physicist would want to be accused of believing in objective reality or
failing to understand the new deep philosophical principles that quantum
mechanics has revealed. (Fortunately there are notable exceptions to this,
but I think the lesson from this fairy tale is clear.)

The work of Kuhn provides the second answer. Thomas S. Kuhn was educated
as a physicist, but has spent his life as a historian of science. In
his investigations he concluded that far from seeking revolutionary new
ideas scientists abhor them. For if you are professional physicist, a
major revolution in physics is likely to be disruptive to your career and
thus your personal life. Being a human being first and physicist after that
major revolutions in your field are real personal threats. The more stature
and prominence you have obtained the greater the threat.

Just think about what will follow when they finally do the experiment
correctly and observe those pesky little time delays that preserve locality. 
Much of leading edge theoretical physics of today will be out the window.
If the wave function is an objective physical entity that is consistent with
locality, an entirely new approach will be needed. High energy physics
will still be of some interest, but the focal point of leading edge research
will shift to understanding the space-time structure of quantum collapse.
The priority of high energy physics will decline dramatically. Billions
will no longer be available for building superconducting-supertoys. For
there will now be an experimental window opened to an entirely new class
of physical phenomena. Unlike the events observed in particle accelerators
that have little or no practical significance, quantum collapse is
a universal process. Every time every transistor in a computer chip changes
state, quantum collapse is involved. Understanding this process will be
of the highest theoretical and the highest practical importance.

Lets do the experiment correctly and soon. It is almost time to start working
on twenty-first century physics.

Paul Budnik

 * Origin: The Electronic Mailbox (1:348/7.0)
Newsgroups: sci.physics