What have you learnt today?

[Montmorency]

Interesting.

To recap, violations of Bell's Inequalities by local hidden-variable statistical models as opposed to Copenhagen entanglement concepts have led to a flawed consensus view that quantum non-localities are ultimately entailed given most sets of assumptions.

Now, though, I've found a paper that throws a wedge between both positions.

As argued at the end of subsection II B and subsection III C, since action is evaluated in
configuration space instead of in ordinary space, then the random fluctuation of infinitesimal
stationary action with respect to the whole ‘system+apparatus’ is not separable into the
fluctuation pertaining to the system and that pertaining to the apparatus. This is explicitly
reflected in the inseparability of wave function of Eqs. (48) or (60). Like the corresponding
classical model, here the atomic degree of freedom plays the role as the apparatus. The
total wave function becomes entangled due to interaction. The whole system+apparatus
must then be regarded as a single unanalyzable whole, both fluctuates together inseparably.
Hence, unlike measurement in classical mechanics discussed in the previous section in which
the interaction Hamiltonian conserves the relevant component of the angular momentum of
the particle being measured, in the statistical model, the same component of the angular
momentum prior to measurement is inevitably disturbed.

Hence, since entanglement and Born’s rule are responsible for the quantum mechanical
violation of Bell’s inequalities and the former are emergent within the local-causal statistical
model satisfying Bell’s locality assumption, then nonlocality must not be blamed as the
source of violation. Moreover, since the predictions of quantum mechanics is confirmed
very accurately by numerous experiments, neglecting all the complexities that might arise
due various potential experimental loopholes, one may conclude that Nature does not use
nonlocality to violate the Bell’s inequalities.

The basic idea seems to be:

Local hidden-variable models actually predict entanglement, but not non-local entanglement, so the violation of Bell's Inequalities by hidden-variable models cannot be used to argue for the existence of quantum non-localities.


My confusion is that, I can't understand how the concept of "emergent" entanglement in the paper relates to the standard descriptions of entanglement I've read about and seen argued against.



But either this way (this post) or that (posts above), it seems the idea of non-local causation is completely unfounded.