SCS

Superluminal Effects

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This is Dr. Little's reply to the question posed by Sarah.

There are so many things physically wrong with a theory of superluminal communication that I hardly know where to begin, but here goes:

Superluminal communication has been offered as an alleged cure for the contradictions implied by the nonlocality found in quantum mechanics and allegedly demonstrated experimentally in EPR experiments. Some have gone so far as to assert that this nonlocality proves the existence of superluminal communication, thereby refuting the theory of relativity.

The first thing wrong with this theory is that it doesn't work. Convincing proofs have been devised demonstrating that any sending of a signal, superluminal or otherwise, from one side to the other of an EPR type experiment would necessarily alter the observed statistics and thus would be in contradiction with the observed results of the experiment. To quote David Bohm, sending such a signal "would require that there be something that we could do, for example, to particle A which would change the statistical result of measurements on the spin of particle B in one or more directions. We shall show that this is, in fact, impossible . . ." [D. Bohm and B. J. Hiley, The Undivided Universe, Routledge, Paperback edition (1995), p. 139.]

Superluminal communication is nothing more than one more attempt to `fix' quantum mechanics by adding new variables, or `hidden variables' as they are frequently termed, to quantum mechanics. The possibility of accomplishing this has been refuted countless times in every imaginable `interpretation' of quantum mechanics. The only possible route to fixing quantum mechanics is through recognizing that the contradictions stem from an error in the theory as it stands, and not from the absence of some alleged hidden variables.

The advocates of superluminal communication usually place it within the context of Bohm's interpretation of quantum mechanics. The idea is that Bohm has reduced all the "quantum weirdness" down to the nonlocality in his quantum potential, and the nonlocality is then removed via superluminal communication, and, voila, a rational theory. The advocates of Bohm's approach consider his theory to be less 'weird' by virtue of the fact that particles are particles, waves are waves, potentials are potentials, unlike what one finds, for example, in the Copenhagen interpretation. What must be recognized is that Bohm's interpretation is, if anything, considerably more 'weird' than any of the other interpretations.

Bohm's quantum potential is not like any other potential. When a particle pair is created, for example, the corresponding 'potential' springs into existence instantaneously everywhere in the universe where either of the two particles might travel. The instantaneous appearance everywhere in the universe occurs even in the 'relativistic' version of the theory. Furthermore, the potential does not decrease with distance from the particles; it exists throughout the universe with undiminished intensity everywhere. Every point communicates information to every other point instantaneously. (The term Bohm uses to describe this is "wholeness".)

The phrase "nonlocal interaction" appears to imply a physical interaction or signal of some kind between two locations within the potential. But, as Bohm makes very clear, the nonlocality found in his quantum potential cannot be understood in any such manner. The 'communication' between two points in the quantum potential simply occurs, instantaneously-that is, by no physical means. It is 'just there' when the potential springs into existence. Nonlocality is not the result of physical communication or of any other factor, but instead is a fundamental aspect of reality.

This is supposed to be a more physically reasonable picture than wave-particles?!?

The alleged nonlocality in EPR experiments is of this 'just there' variety. By its very nature, it is not explainable through any kind of real, physical communication between the two sides, superluminal or otherwise. The nonlocal transfer of information just happens-by no means. (The wholeness did it.)

Bohm's theory is nothing but a 'rewiring' of the very same quantum mechanics one finds in all the other interpretations, with the same internal error: the waves moving in the wrong direction. The resulting contradictions take a different form with Bohm, but they are contradictions nonetheless.

A simpler and more obvious reason why superluminal communication won't account for EPR experiments is the fact that one can rotate the polarizers on both sides of the experiment simultaneously. In order to explain this, the communication would have to be instantaneous. And instantaneous means instantaneous, not very very fast. Indeed, if one has not already rejected relativity theory, superluminal communication in one frame of reference would imply backwards in time communication in other frames.

Which gets us to what is certainly the most overwhelming objection to superluminal communication: it contradicts and requires the total rejection of the theory of special relativity. Relativity theory has been confirmed by more experiments, and to a greater degree of accuracy, than perhaps any other theory in the history of science. Superluminal communication contradicts the findings of all of these countless experiments.

Bohm has tried to avoid this conclusion by distinguishing between the world of observation and the 'real' world lying behind it. (He probably wouldn't state the matter in these terms, but this is what his approach amounts to.) Bohm argues that his instantaneously propagating quantum potential doesn't violate relativity because we don't directly perceive the quantum potential. What we do perceive -- the results of any experiment -- are predicted by his theory to conform to the postulates of relativity. So he dispenses with relativity as being merely a set of relationships between observations (as if one can observe nothing), not relationships between real objects and events. Amazingly, Bohm terms his interpretation of quantum mechanics the "ontological" interpretation, thereby attributing reality to his thoroughly illogical and unphysical quantum potential, while simultaneously denying reality to the phenomena of relativity, a theory that we now know from TEW to have a very simple, logical, physical explanation.

Relativity theory is not merely a surface description of relations between experimental dial readings. It is a thoroughly validated theory regarding the way things are in reality. Anyone who claims relativity theory is false, as do the superluminalists, must begin by offering a valid alternative explanation for the thousands of experiments confirming it.

To the best of my knowledge, no advocate of superluminal communication has offered anything approximating a physical theory as to how the communication takes place, much less any valid alternative explanation for the phenomena of relativity. Even if one hasn't yet discovered the alleged objects that carry out the alleged communication, the very least one should expect before taking the idea seriously is a mathematical/behavioral formalism of some sort that yields the results observed in the laboratory. But of course this hasn't been done because it is mathematically impossible. Pulling superluminal communication out of a hat to account for EPR is, in the absence of any such formalism or theory, little better than attributing the effect to magic. The further claim that this magic-equivalent provides the basis for the overthrow of special relativity has to be one of the most absurd claims ever made in the history of physics.

A belief in magical communication between objects was characteristic of the thinking of ancient Chinese mystics. The 'thinking' of the advocates of superluminal communication, and for that matter, the thinking of the advocates of Bohm's quantum mechanics interpretation, including Bohm himself, is little more advanced -- not to imply that the thinking of the advocates of any other interpretation of quantum mechanics is much better.

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