Quantum Gravity from Quantum Computation

One Reply to “Quantum Gravity from Quantum Computation”

1. Whether or not this paper truly makes sense is beyond my limited (undergraduate) abilities. I grasped a good deal of the front matter, but I’ll be damned if I can follow the rest. The most easily understandable and notable points seem to be made not only in the introduction but, for some reason, in the appendix. Perhaps its more common to discuss implications of a new theory in an appendix than I believe it to be, but it surprised me. I can’t vouch for the coherence of these statements but they struck me as big, bold statements.
   From A3.4, pg 27:

   A fluctuating cosmological term then arises naturally…This picture of a fluctuating cosmological ‘constant’ with a scale given by the age of teh universe is consistent with the causal set account of a fluctuating cosmological term.

   From A3.5 (the necessary discussion about “scaling up” to the classical world):

   In other words, the computational universe naturally gives rise to the a semiclassical spacetime via the decoherent histories approach to quantum mechanics…Coarse-graining about stable histories yields hydrodynamic variables that approximately decohere and obey classical probabilites.

   There’s a ton more back there, each just as interesting as the next. I’m still trying to grok it all, but it seems to be in a very clear language that doesn’t mark immediately as going into the crank file. I guess I’ll stay agnostic on this until, at the very least, I’m able to say more about gen. relativity beyond “er.. its about spacetime telling matter how to move and matter telling spacetime how to curve.. oh, and there’s tensors everywhere”.
   I suppose my next question is, could you point me to some discussion on this paper? Perhaps, somewhere I might see more in the future besides watching Arxiv like a hawk? I suppose it’s a bit early, but some follow up in your blog would be great when this little paper comes into focus in the larger community.

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