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A comment on Quantum Mechanics for Programmers. Parent comment

Re:Quantum Mechanics for Programmers by chriswarbo on Thursday March 30, 2017 @11:37AM (#13996286)
Let's say I toss a fair coin; before I look at it, the outcome is indeterministic to me: there's a 50/50 chance of heads or tails. Once I look at it, I gain 1 bit of information. To another experimenter, the 'me + coin' system is indeterministic: it's either me seeing heads or me seeing tails. Once I tell that experimenter the outcome, they gain 1 bit of information. To a different experimenter, the two of us with the coin is indeterministic... and so on.

Is this scenario fundamentally different than the quantum system? Is this scenarion also a "problem"?

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Re:Quantum Mechanics for Programmers by akvadrako on Thursday April 06, 2017 @11:27AM (#14051409)
What you just described is a hidden variable model which cannot reproduce the behavior of entangled particles. For details look up Bell's theorem.
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Re:Quantum Mechanics for Programmers by chriswarbo on Wednesday April 19, 2017 @08:17PM (#14152950)
Oh I'm well aware of Bell's theorem; I'm a trained Physicist :)

Bell's theorem rules out theories of local hidden variables. It says nothing about non-local hidden variables, or even something more mundane like determinism (sometimes referred to as "superdeterminism").

In any case, I'm not sure Bell's theorem has much impact on my question: why is one of these things (transfer of information from a coin toss) not a problem, conceptually; whilst the other (entanglement of quantum systems) is a problem, conceptually?

(Personally, I don't find either particularly troubling; just curious to know what the philosophical distinction is, without appeals to "quantum weirdness")

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Re:Quantum Mechanics for Programmers by akvadrako on Wednesday April 26, 2017 @09:48AM (#14202877)
A classical analogue to entanglement is not problematic for causally connected processes and in some cases it's a good model, like with human reasoning or neural networks. QM is a generalisation of bayesian reasoning that can handle non-commuting variables.

Yet entanglement is observed non-locally, even backwards in time or between degrees of freedom that never co-exist. Nobody has been able to create a non-local model that doesn't require fine tuning and the idea goes against the spirit of special relativity.

Thus, I would agree with you, there is no "problem" with entanglement. Except non-locality.

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