08 February, 2001
The Editor
New
Scientist
Dear Sir
Enough is
enough! It so happens that I have made
a study of the various “quantum entanglement” experiments – not all of them, of
course, but enough to know that there is more than the one explanation
available! How is it that we are told
only the one? How can Anil Ananthaswamy
(“All tied up”, February 9, page 5) come up with statements about the “bizarre
property that allows two particles to behave as one, no matter how far apart
they are”?
Oh to get
back a 100 years or so, to the days when people did consider the
alternatives! The halcyon days before
the New York Times made its earth-shattering discovery that Einstein was a
genius (His “spacetime” had been confirmed by Eddingtons’ observations of the
1919 eclipse. Subsequent analyses cast severe doubt on this, but the damage had
been done[1].)! Don’t you realise that
there is not a single experiment that really forced quantum theory on
us? Up until Alain Aspect’s famous Bell
test experiments of 1981-2 [2] it was allowable to doubt. Were Aspect’s experiments so conclusive that
we were forced into the new paradigm, forced to relinquish that precious
assumption of “local realism” that had stood us in such good stead, not only in
physics but in the totality of our experience?
No!
Each and
every experiment to date that is supposed to show quantum entanglement has had
“loopholes”. Certainly, in the opinion
of the experts these loopholes are unlikely to prove quantum theory wrong. In the opinion of the experts, the proposed
“loophole-free” experiment (proposed by Edwin Fry in 1995 [3] and still
experiencing technical difficulties) is bound to support quantum theory. But in the meantime, could we not keep an
open mind? We have been told there is
no alternative, but this is simply not true.
What is true is that it
has not proved possible to persuade the top journals such as Physical Review
Letters to publish papers that reveal them [4]. It is also true, of course, that the vast majority of claims of
alternative explanations are false, but every once in a while someone
re-discovers those loopholes that have been so quietly ignored. They find that ordinary “classical” ideas
have been available all along, just needing slight extensions to cover such
practicalities as the behaviour of real light detectors [5]. These local realist ideas lead to
explanations that don’t agree exactly with quantum theory, but the do
agree with the experiments.
To return
to that February 9 letter: Did Zeilinger’s laboratory really show that
buckyballs could be put in a “superposition of states” [6]? No!
Quantum theory chooses to describe any setup that shows
interference-type patterns in this language, but there is always an
alternative. One possibility, almost
equivalent to the quantum theory story, is that there are coherent
electromagnetic waves accompanying the buckyballs, with which the latter are
able to couple. The waves pass through
the slits and suffer interference. The
molecules pass through too. Their
positions are influenced by the waves — they tend to move towards nodes or
antinodes, depending on the physical process involved. No conceptual difficulty; no superposition,
just the kind of classical resonance coupling that Hendrik Lorentz knew about
100 years ago [7].
Hasn’t
quantum theory had a long enough run for its money? If it had stuck to calculations of the frequencies of atomic
spectra I could have forgiven it, but if it tells us that we have to abandon
the principle of local causality, never!
Yours
sincerely
Caroline H
Thompson
Refs:
[1] Collins, Harry and Trevor Pinch, The
Golem: What everyone should know about Science, (Cambridge University
Press, 1993).
[2] Alain Aspect, et al.,
Phys. Rev. Lett. 47, 460 (1981); 49, 91 (1982) and 49,
1804 (1982).
[3] Fry, E. S., Walther, T. and Li, S.,
Proposal for a loophole-free test of the Bell inequalities, Phys. Rev. A 52,
4381 (1995).
[4] Thompson, C. H., "The Tangled
Methods of Quantum Entanglement Experiments", Accountability in
Research, 6 (4) 311-332 (1999).
[5] Thompson, C. H., "The Chaotic Ball:
An Intuitive Analogy for EPR Experiments", Found. Phys. Lett. 9,
357, http://arXiv.org/abs/quant-ph/9611037 ; “Subtraction of ``accidentals'' and the validity of Bell tests” (1999), http:// arxiv.org /abs/quant-ph/9903066.
[6] Arndt, M. et al., "Wave-particle duality of C60
molecules", Nature 401, 680-682 (1999).
[7] Lorentz, Hendrik A, “Theory of Electrons”,
(Teubner, 1916).
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