ueit said:
I don't think that a full QFT computation of such a complex system is possible. Last time I've checked the most complex system that has been solved was a two-particle system (pion). A three particle one (neutron, proton) was already too hard. So, nobody knows what exactly a quantitative QFT treatment of an EPR experiment would reveal.
What you seem to miss is that in no matter what quantum theory (or for that matter, bohmian mechanics or whatever), we *specify externally* what are the measurements we are going to do. The theory can give an answer no matter what external input we use as "measurement settings". You don't have to follow through any complicated calculation to *find out* what measurement one is going to do, you put it IN by hand - in fact, there is not even any sensible way in which one could calculate, from first principles, what measurement one would do! EVEN if you could follow up through all the calculations - which is impossible in quantum theory, as well as in classical theory, and probably in ANY theory, current or future - you would still have to specify EXTERNALLY what's the measurement that is going to be performed (the choices of the angles, or the system that will determine this choice, or whatever) - it would be part of the description of the setup which you can (have to) arbitrarily determine before you could even start your (hopeless) calculation.
In other words, a quantum mechanical "problem description" contains not only the "correct" (superdeterministically correct) measurement settings, but all other, counterfactual, superdeterministically impossible, settings, and nevertheless grinds out an answer.
It is because of this freedom (external freedom, that is, we can do the calculations for all non-superdeterministically possible settings, and not only for the few superdeterministically allowed settings) that it is not going to be possible to demonstrate any *equivalence* between a superdeterministic theory and a non-superdeterministic theory such as quantum theory in all its variants, such as BM, MWI, or whatever.
You see, it is as if in classical mechanics, you would come up with a "super-configurational" theory that states that the positions of the particles also determine their momentum in some hidden way, and that this explains entirely classical mechanics. Now, you are not going to be able to show any equivalence with classical mechanics, because in classical mechanics, you are FREE to pick any momentum you like with a given particle configuration. You can do the classical calculation for all the "impossible" momentum assignments too out of which the "super-configurational" theory only picks one or a few possible ones. You are never going to be able to show that picking these few are going to be equivalent to the workings of classical mechanics, as most of the classical mechanics "initial conditions" are impossible in the new theory.
The only way to show this, is to demonstrate that if you do the entire calculation for those few specific allowed initial conditions, you nevertheless end up each time with all possible observable results from classical mechanics, with well-chosen initial conditions.