Re:The Trouble with Quantum Mechanics (2017) [pdf]
by meroes on Thursday August 20, 2020 @03:49PM
(#24227943)
You say nonlocality isn't negotiable but I think one of Bell's assumptions isn't met in MW, namely single outcome of experiment. I think this is shown in that table as the local dynamics column.
But then without nonlocality nor hidden variables, I truly am at a loss how quantum computers even work according to MWI. But I know this area gets so complex so fast.
Yes, the Copenhagen interpretation says that the wavefunctions we manipulate are epistemic; they exist in our mind and on the blackboard but not necessarily IRL. The epistemic toy theory [1] makes this concept very concrete, although note that that theory has hidden local variables and thus doesn't correctly implement Bell/KS/Free Will.
Yes, MWI is quite ontic; it's probably the most ontic that a QM interpretation can be, since it insists that all possibilities exist. Just like modal realism, MWI is the most extreme of the phrasings in that direction.
Non-locality sadly isn't negotiable anymore. Bell's inequalities have been violated in laboratories well enough to my satisfaction [2], so theories that can't handle it need to be fully rejected. I'm not sure what's left; maybe the transactional interpretation?
[0] https://en.wikipedia.org/wiki/Interpretations_of_quantum_mec...
[1] https://arxiv.org/abs/quant-ph/0401052
[2] https://en.wikipedia.org/wiki/Bell_test_experiments