July 22, 2012
Recently, Gerard 't Hooft published his own version of superstring theory.
"Ideas presented in two earlier papers are applied to string theory. ... We now also show that a cellular automaton in 1+1 dimensions that processes only ones and zeros, can be mapped onto a fermionic quantum field theory in a similar way. The natural system to apply all of this to is superstring theory ..." (*)
The earlier papers he refers to describe a duality between a deterministic cellular automaton and a bosonic quantum field theory in 1+1 dimensions and argue that Born's rule strongly points towards determinism underlying quantum mechanics (x).
All this is far from the mainstream, but 't Hooft is a physicist not a crackpot and so he points out problems of his proposal(s) in his papers, e.g. he notes that some of his models have an unbounded Hamiltonian and he does discuss the apparent contradiction with Bell's inequality.
(*) It is known for a long time that the Ising model is equivalent to a fermionic field in 2 dimensions (see e.g. this paper for references).
(x) Quantum theory without the Copenhagen 'collapse' is a deterministic theory, so it is not too surprising if one finds such a duality. But it is unusual that Born's rule 'strongly points towards' determinism.
added later: Peter Shor explains why it is unlikely that this will ever lead to anything, while 't Hooft seems super-determined to continue his project.