Quantum Mechanics: Not Just a Matter of Interpretation
It has been widely accepted that the rival interpretations of quantum mechanics, e.g., the Copenhagen Interpretation, the Many-Worlds Interpretation, and my father John Cramer‘s Transactional Interpretation, cannot be distinguished or falsified by experiment, because the experimental predictions come from the formalism that all such interpretations describe. However, the Afshar Experiment demonstrates in an interaction-free way that there is a loophole in this logic: if the interpretation is inconsistent with the formalism, then it can be falsified. In particular, the Afshar Experiment falsifies the Copenhagen Interpretation, which requires the absence of interference in a particle-type measurement. It also falsifies the Many-Worlds Interpretation which tells us to expect no interference between “worlds” that are physically distinguishable, e.g., that correspond to the photon’s passage through one pinhole or the other.
Fascinating discussion in the comments.
Seach under “Vaidman bomb” for an interesting take on interaction-free measurements. This is related to the “seeing with no light” article in Scientific American a few years back. Surprisingly, one can build experiments which have radically different results contingent on adding a component with arbitrarily small probability epsilon of interacting. The bomb part is phrase this way: Suppose I have a photo-detector connected to a bomb trigger. With what probability can I determine that the photodetector is there or not without setting off the bomb? The answer is I can do this with arbitrary small probability of setting off the bomb. This sounds very similar to Cramer’s description of Afshar’s result, and is perfectly understandable in all three interpretations of quantum mechanics.
more…
Sorry, folks. The waveform was collapsing along nicely there for a while, but in pure non-deterministic fashion, we’re back to no one actually knowing anything…