Once you get into field theory you have x, y, z and t all treated as coordinates, not operators. The universe realio trulio starts to look like a 4-dimensional object, and reference frames are just slices of this 4-dimensional object. And I guess you're right, if you don't use relativstic quantum mechanics, you won't have all the nice relativstic properties.
If you want your probabilities to be frequencies, I suppose you could work out the results if you wanted. The run-of-identical-experiment frequencies should actually be pretty easy to calculate, and will give the same answer whether or not you collapse, for obvious mathematical equivalence reasons. And if that's good enough for you to accept that the outputs of ordinary quantum mechanics "really are" probabilities, maybe it will be good enough for slightly less ordinary quantum mechanics.
A better exercise to explore the unique probabilities in MW might be to show that, if our observer gets totally entangled with a series of two-state systems, the probabilities given by the partial density matrix evolve according to the rules you'd expect from collapse. Note that this isn't just another boring mathematical equivalence. Humans are interactions between a bunch of multi-state systems. If we evolve in a way that looks like collapse, we'll see something that looks like collapse!
The universe realio trulio starts to look like a 4-dimensional object, and reference frames are just slices of this 4-dimensional object.
But the quantum wavefunction isn't a four-dimensional object. If we're doing field theory, it's an object in an infinite-dimensional space. The four-dimensionality of field theory resides in the operators, not the wavefunctions. So if I say that the observables corresponding to operators are what's real, I can think relativistically about space and time, because everything that's real is always anchored to a specific p...
These are extracts from some Facebook comments I made recently. I don't think they're actually understandable as is—they're definitely not formal and there isn't an actual underlying formalism I'm referring to, just commonly held intuitions. Or at least intuitions commonly held by me. Ahem. But anyway I figure it's worth a shot.
A proposal to
rationalizederive magick and miracles from updateless-like decision theoretic assumptions:(On Google+ I list my occupation as "Theoretical Thaumaturgist". ;P )