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Science and philosophy

Posted Feb11-13 at 06:58 AM by Demystifier

When you systematically collect empirical data on nature and compare them with testable theoretical predictions, that's science. When you SAY that this is what science is, that's philosophy.
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Simplest proof of Bell’s theorem

Posted Dec21-12 at 05:21 AM by Demystifier

Today Lorenzo Maccone presented a very simple proof of the Bell theorem in terms of an inequality:
http://arxiv.org/abs/1212.5214

But I still think that the proof of Hardy in terms of an equality (rather than inequality) is simpler. For a particularly simple form of that proof see e.g. page 17 of
http://arxiv.org/abs/quant-ph/0609163
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Quantum state: Reality or mere probability?

Posted Dec14-12 at 10:26 AM by Demystifier

There is an old controversy in quantum mechanics, with arguments on the borderline between science and philosophy, on the question whether the quantum state describes an objective reality associated with a single system, or mere probability describing properties of a large ensemble of equally prepared systems. The recent PBR theorem* provides the strongest argument so far that the quantum state is real, which elevates the controversy to a higher scientific level.

Here I attach the...
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Many Worlds proved inconsistent?

Posted Nov1-12 at 11:18 AM by Demystifier

In a recent paper entitled
"Nothing happens in the Universe of the Everett Interpretation":
http://arxiv.org/abs/1210.8447
Jan-Markus Schwindt has presented an impressive argument against the many-world interpretation of quantum mechanics.

The argument he presents is not new, but, in my opinion, nobody ever presented this argument so clearly.

In a nutshell, the argument is this:
To define separate worlds of MWI, one needs a preferred...
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A confusing answer to a simple question: What is quantum theory about?

Posted Mar28-12 at 07:05 AM by Demystifier

Quantum theory is called "quantum" because it is supposed to be about quanta - discrete spectrum of certain quantities which in classical theory have a continuous spectrum. But actually, quantum theory does not need to be about quanta at all, because many quantum quantities actually have a continuous spectrum.

If you think it's confusing, then you've seen nothing. Quantum mechanics is (or at least used to be) about Schrodinger equation, which is a quantum theory of electron....
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