The "demonstrated" part is a bit misleading. All they did was to reformulate the Hardy criteria that did not have the part that GHZ objected to. We still have to wait for an experiment using such a scheme.
Sure enough! The title and a quick read led me to think they had actually done the experiment. I'll change the word "demonstrated" to "scheme".
A minor quibble: This demonstrates "non-locality" no more - and no less - than traditional Bell tests with entangled particles. The issue, as is well known, is that such experiments show that either locality OR realism must be rejected to match the predictions of QM. It does not say which of these two must go. The title of the article could have been "Non-Realism of a Single Particle" just as easily - and just as accurately.
Okay, but I'm not changing the title again.
That's a bit superfluous: I don't think many physicists will contemplate abandoning realism at this stage. (Heck, could I even speak of other physicists if I did?)
Very interesting claim, that entanglement is just superposition (a classical wave effect.. basically reduces most of "the mystery" to ol' Fourier math), I'm keen to see how this is received (particular by Zeilinger et al).
Just like all the other experiments of this type it "proves" non-locality (or non-realism) only if other, supplementary assumption is hold true. One must assume that the particles' properties, as they leave the source, are not influenced by the presence of the experimental setup (prism, detectors, Alice & Bob, etc). This is hardly an acceptable hypothesis.
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