But wouldn’t GR still fall prey to the same ‘hard to implement on a TM’ argument? Also, one could define a relational model of computation which does not permit an outside view (indeed the relational QM is such a thing), by the way. It’s not clear which model of computation would be more complex.
With regards to the objective collapse, I recall reading some fairly recent paper regarding the impact of slight non-linearities in QFT on MWI-like superpositions, with conclusion that slight non-linearities would lead to objective collapse which occurs when the superposition is too massive. Collapse does seem unlikely on it’s own—if you view it as some nasty inelegant addition, but if it arises as a product of a slight non linearity, it seems entirely reasonable, especially if the non-linearity exists as a part of quantum gravity. It has been historically common that a linear relationship would be found non-linear as measurements improve. (The linear is simplest, but the non-linear models are many—one specific non-linear model is apriori less likely than a linear one, but the totality of non-linear models is not).
Without collapse you still have the open question of Born’s law, by the way. There been a suggestion to count the distinct observers somehow, but it seems to me that this wouldn’t work right if part of the wavefunction is beamed into the space (and thus doesn’t participate in decoherence of an observer), albeit I never seen a concrete proposal as to how the observers should be counted...
And back to the Turing machines, they can’t do true real numbers, so any physics as we know it can only be approximated, and it’s not at all clear what an approximate MWI should look like.
But wouldn’t GR still fall prey to the same ‘hard to implement on a TM’ argument? Also, one could define a relational model of computation which does not permit an outside view (indeed the relational QM is such a thing), by the way. It’s not clear which model of computation would be more complex.
With regards to the objective collapse, I recall reading some fairly recent paper regarding the impact of slight non-linearities in QFT on MWI-like superpositions, with conclusion that slight non-linearities would lead to objective collapse which occurs when the superposition is too massive. Collapse does seem unlikely on it’s own—if you view it as some nasty inelegant addition, but if it arises as a product of a slight non linearity, it seems entirely reasonable, especially if the non-linearity exists as a part of quantum gravity. It has been historically common that a linear relationship would be found non-linear as measurements improve. (The linear is simplest, but the non-linear models are many—one specific non-linear model is apriori less likely than a linear one, but the totality of non-linear models is not).
Without collapse you still have the open question of Born’s law, by the way. There been a suggestion to count the distinct observers somehow, but it seems to me that this wouldn’t work right if part of the wavefunction is beamed into the space (and thus doesn’t participate in decoherence of an observer), albeit I never seen a concrete proposal as to how the observers should be counted...
And back to the Turing machines, they can’t do true real numbers, so any physics as we know it can only be approximated, and it’s not at all clear what an approximate MWI should look like.