DrChinese said:
QFT has a problem explaining how Alice and Bob sync up without any nonlocal action occurring.
I disagree with this as you state it. I would state it as:
Some interpretations of QFT have a problem explaining how Alice and Bob sync up,
according to proponents of other interpretations.
QFT predicts the correlations between Alice and Bob just fine. There is no problem in matching theoretical predictions to experimental results. As far as I can tell, everyone agrees on that.
What everyone does
not agree on is interpretation--on what kind of story to tell in ordinary language in order to "explain" why the experimental results are what they are. When you say "without any nonlocal action occurring", this "nonlocal action" thing does not come from experimental results. There is no big light that goes on when an experiment is finished that says "Nonlocal action here!" There are just correlations that violate the Bell inequalities. Which, as I have just noted, QFT predicts just fine. And there is no label pasted on any part of the QFT calculations that says "Nonlocal action here!" There are just the predictions of Bell inequality violation. Does that count as "nonlocal"? Depends on whose definition of "nonlocal" you want to use. There is no single definition that everyone agrees on.
DrChinese said:
Every physicist here is aware of the essential experimental difficulty (which you seem to both accept and deny in alternating posts)
The difficulty is not experimental. It's not even theoretical, since the theory predicts the experimental results just fine. The difficulty is with interpretation.
DrChinese said:
which no theory (or interpretation) explains to the satisfaction of the physics community
Theories aren't in the business of explaining things by generating interpretations. Theories are in the business of explaining things by making predictions that differ from the predictions of other theories, and then winning out over those other theories when the predictions get tested by experiment.
"Interpretations", IMO, are what we fall back on when we don't have competing theories to test. We don't have competing theories of QM/QFT that make different predictions. (Some have been tried--for example, the GRW stochastic collapse theory--but so far no alternatives have panned out.) We just have a set of predictions that seem counterintuitive, and a bunch of different interpretations that tell different stories about why the predictions come out the way they do, but which can't be tested against each other because they all make the same predictions.
My personal preference in such a situation is not to insist on
any particular interpretation, but to accept the fact that, for now, we don't have a single, accepted way to explain why quantum systems behave the way they do. Trying to concoct more interpretations won't help. What will help is figuring out more follow-on theories that extend QM/QFT in different ways, making different testable predictions, and then testing them. That's how progress is made in science.
But if anyone wants to insist on talking about interpretations, at the very least, one has to recognize that, since, as you agree, there is no interpretation that explains things to everyone's satisfaction,
all interpretations have to be treated as personal opinions that cannot be tested by experiment. And that means that
you cannot talk about features of particular interpretations as if they were requirements that all intepretations had to meet. "Nonlocal action" is a feature of particular interpretations. It is not a requirement that every interpretation has to meet.