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Entanglement Could Be a Deterministic Phenomenon
KentuckyFC writes "Nobel prize-winning physicist Gerard 't Hooft has joined the likes of computer scientists Stephen Wolfram and Ed Fredkin in claiming that the universe can be accurately modeled by cellular automata. The novel aspect of 't Hooft's model is that it allows quantum mechanics and, in particular, the spooky action at a distance known as entanglement to be deterministic. The idea that quantum mechanics is fundamentally deterministic is known as hidden variable theory but has been widely discounted by physicists because numerous experiments have shown its predictions to be wrong. But 't Hooft says his cellular automaton model is a new class of hidden variable theory that falls outside the remit of previous tests. However, he readily admits that the new model has serious shortcomings — it lacks some of the basic symmetries that our universe enjoys, such as rotational symmetry. However, 't Hooft adds that he is working on modifications that will make the model more realistic (abstract)."
It's not really valid, though; it makes a false distinction between "a hidden variable" and "a hidden variable controlled by another hidden variable" as if they were different. Bell's theorem covers (or at least appears to cover) any additional information or state, regardless of the theory or process involved, provided that state is "attached" to the entangled particles (that is, it's local).
Hidden variables in this case should be thought of as a hidden micro-states. A hidden variable theory would have quantum mechanics be something like thermodynamics; i.e., a theory that is not really basic, but appears so as we cannot see the fine scale true reality. Einstein was convinced that this had to be the case.
The tests of Bell's Theorem shows that no locally causal hidden variable theory is viable. This says basically that one of these must be the case
There are no hidden variables (i.e., true quantum uncertainty applies, and quantum mechanics is correct).
The speed of Light can be violated (i.e., there are hidden states that can exchange information faster than the speed of light). This implies, by the way, causality failures would be possible, so that in principle you could do something like kill your grandfather and prevent your own existence.
There is action at a distance (i.e., the theory is non-local).
There has long been a viable theory, that of Bohm, that replicates normal quantum mechanics. It's non-local.
I cannot tell from a read of the article (and without seeing the underlying paper) if 't Hoof has a non-local theory or just how he stays consistent with Bell's Theorem.