Curt Jaimungal Interview With Robert Spekkens

With an advert for some erectile dysfunction chewing gum, ... for all the cock-bitten men, I guess.

My comment:

I would love to hear someone explain Bell's theorem as clearly as he explained causal explanations and epistemic quantum states. 46:17 People talk about non-locality as if it is obvious, but epistemic quantum states are inherently non-local: you only know that Alice and Bob's measurements are correlated when you also know that Alice and Bob each indeed do have one of a single pair of entangled particles. Similarly, you can only compare the settings of Alice and Bob's measuring apparatus if you also have some observational procedure for verifying their relative orientations along the paths of the particles, then you also need to know that those paths are in free space and that there is no field which is preparing a different state, and so-on and so-forth. So when Spekkens says that Bell's theorem is a no-go for such-and-such a set of hypotheses then he doesn't say anything at all to me because the actual hypotheses (non-locality in this example) are so vague. He seems to be quite clear at 1:11:19 but maybe I'm underestimating the complexity of the argument. If you look at that paper "A structure theorem for generalized-noncontextual ontological models" then it's clearly a lot of work to characterise a class of ontological models. [See also 2:03:44 where he says why he studies these ontological models, 2:12:30 I think he must agree with me!]

See A structure theorem for generalized-noncontextual ontological models by David Schmid, John H. Selby, Matthew F. Pusey and Robert W. Spekkens.

1:33:36 Ballentine's Ensemble Interpretation see his 1970 Rev. Mod. Phys. paper The Statistical Interpretation of Quantum Mechanics:

The Statistical Interpretation of quantum theory is formulated for the purpose of providing a sound interpretation using a minimum of assumptions. Several arguments are advanced in favor of considering the quantum state description to apply only to an ensemble of similarily prepared systems, rather than supposing, as is often done, that it exhaustively represents an individual physical system. Most of the problems associated with the quantum theory of measurement are artifacts of the attempt to maintain the latter interpretation. The introduction of hidden variables to determine the outcome of individual events is fully compatible with the statistical predictions of quantum theory. However, a theorem due to Bell seems to require that any such hidden-variable theory which reproduces all of quantum mechanics exactly (i.e., not merely in some limiting case) must possess a rather pathological character with respect to correlated, but spacially separated, systems. 

2:23:42 See ψ-epistemic models are exponentially bad at explaining the distinguishability of quantum states by M. S. Leifer.

See https://www.rwspekkens.com/.

See also Gabriele Carcassi on Why Statistical Mechanics is Fundamental in Physics.

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