3 ms·

Shame, Atiyah was senile at that point. A sad note to end on after a brilliant career. But whatever you may think about him, Wolfram is not senile.

lanstin 5y ago
The book is under-whelming, however. There might be something worth investigating, although the basic mapping between finite automata and QFT is not made explicit, nor even how it could be. One type of maths is pretty firmly embedded in continuous maths on manifolds and the other is inherently discrete. And one has probability density and is only deterministic in the calculation of the probability densities, while the other is apparently completely deterministic. And how can non-local entanglement occur with the automata model? That said, there are some interesting hints in modern physics that information is related to some very fundamental processes, e.g. the entropy of black holes being related to information held by the black hole, etc. But he (in my opinion, a mathematically advanced amateur, and no master of QFT) has too much excitement for his own idea and too much hand-waving over the details. I did buy and read most of it, as I also have bought many of Penrose's popular books, so perhaps I'm just a disgruntled purchaser.
- taliesinb 5y ago
  I largely agree about the book: I think there might be something there, but the case is far from being made. One small correction: the rewriting systems he proposes are not deterministic. As for how non-local entanglement can occur, I'll just offer my current speculation, having spent about a year working on this kind of approach. You'll have to give up SR in its traditional sense. There will be a preferred reference frame, which is the rule application order that the automata uses in any particular history. The challenge becomes to explain why it is not observable and you have approximate Lorentz covariance. I think this will be less hard than one imagines -- even in Feynman's lectures you see explanations of SR that involve an aether (or a global frame if you prefer) and clocks defined by light bouncing between mirrors moving in this aether. Of course all physical laws have to be covariant, and explaining how this happens requires you to know how the physical laws are "microphysically". But the graph itself in graph-automata models is a good candidate for an ether, with particles being e.g. topological defects. Somehow covariance must reflect how a dynamical account of defect behavior changes as one foliates rule application order, mysterious but not inconceivable. Now, entanglement: one imagines entanglement is implemented by long-range connections, which in graph-type models could take many forms. This is a kind of discrete version of the "ER = EPR" proposal. But they will have to be such a limited form of connection that they do not permit signaling, and I think they way they can do this is via some sort of knot-theoretic braiding. Only be comparing measurement outcomes classically will it be possible to deduce the way the braiding was effected by measurement and confirm you had e.g. a GHZ state. Now, QM is more than just entanglement, but in the words of Jaynes: "QM is a peculiar mixture describing in part realities of Nature, in part incomplete human information about Nature - all scrambled up by Heisenberg and Bohr into an omelette that nobody has seen how to unscramble." When scrambled, all the ingredients look inextricably connected. I think the unscrambling will seem beyond hope until one has the exact recipe to recreate the omelette.

lanstin 5y ago

The book is under-whelming, however. There might be something worth investigating, although the basic mapping between finite automata and QFT is not made explicit, nor even how it could be. One type of maths is pretty firmly embedded in continuous maths on manifolds and the other is inherently discrete. And one has probability density and is only deterministic in the calculation of the probability densities, while the other is apparently completely deterministic. And how can non-local entanglement occur with the automata model? That said, there are some interesting hints in modern physics that information is related to some very fundamental processes, e.g. the entropy of black holes being related to information held by the black hole, etc. But he (in my opinion, a mathematically advanced amateur, and no master of QFT) has too much excitement for his own idea and too much hand-waving over the details. I did buy and read most of it, as I also have bought many of Penrose's popular books, so perhaps I'm just a disgruntled purchaser.

taliesinb 5y ago
I largely agree about the book: I think there might be something there, but the case is far from being made. One small correction: the rewriting systems he proposes are not deterministic. As for how non-local entanglement can occur, I'll just offer my current speculation, having spent about a year working on this kind of approach. You'll have to give up SR in its traditional sense. There will be a preferred reference frame, which is the rule application order that the automata uses in any particular history. The challenge becomes to explain why it is not observable and you have approximate Lorentz covariance. I think this will be less hard than one imagines -- even in Feynman's lectures you see explanations of SR that involve an aether (or a global frame if you prefer) and clocks defined by light bouncing between mirrors moving in this aether. Of course all physical laws have to be covariant, and explaining how this happens requires you to know how the physical laws are "microphysically". But the graph itself in graph-automata models is a good candidate for an ether, with particles being e.g. topological defects. Somehow covariance must reflect how a dynamical account of defect behavior changes as one foliates rule application order, mysterious but not inconceivable. Now, entanglement: one imagines entanglement is implemented by long-range connections, which in graph-type models could take many forms. This is a kind of discrete version of the "ER = EPR" proposal. But they will have to be such a limited form of connection that they do not permit signaling, and I think they way they can do this is via some sort of knot-theoretic braiding. Only be comparing measurement outcomes classically will it be possible to deduce the way the braiding was effected by measurement and confirm you had e.g. a GHZ state. Now, QM is more than just entanglement, but in the words of Jaynes: "QM is a peculiar mixture describing in part realities of Nature, in part incomplete human information about Nature - all scrambled up by Heisenberg and Bohr into an omelette that nobody has seen how to unscramble." When scrambled, all the ingredients look inextricably connected. I think the unscrambling will seem beyond hope until one has the exact recipe to recreate the omelette.