Re: Question on quantum computing and many-worlds interpretations of Quantum Mechanics

Iain,
    First of all, Deutsch's claim for a multiverse was only in the event that a quantum computation could be done that was so large that the number of requisite interim results exceeded the number of elementary particles in this universe. Not in our lifetime. But, as Phil pointed out in his post, it's not at all clear that the number of these so-called interim results in a quantum computation are limited by the number of particles. Suppose, however, such alternate universes really did exist, despite the lack of evidence. Since none of the alternate universes can impact this universe, as far as we know, it is totally meaningless and any speculation on theological implications is specious. It gets more interesting, however, if you postulate that dark matter or dark energy is a result of the influence of either alternate universes, or, more likely, other branes. Personally, I'm a skeptic of string theory and prefer loop quantum gravity ideas but I still like to speculate on the impact of alternate branes. Maybe the "new heaven and the new earth" are on another brane and we move smoothly and seamlessly from one brane to another.

Randy
  ----- Original Message -----
  From: Iain Strachan
  To: asa
  Sent: Thursday, March 02, 2006 5:32 PM
  Subject: Question on quantum computing and many-worlds interpretations of Quantum Mechanics

  This is possibly a naive question that occurred to me, which might be down to my limited knowledge of the subject.

  The possibility has been raised on the list of the idea of quantum computing being able to solve problems such as factorization of very large numbers, that could not be done on a conventional computer because of the numbers of calculations required. The success of a quantum device therefore necessitates the existence of parallel universes ( multiverses ) in order for all the computations to be carried out in parallel.

  This in turn raised worries of a theological nature. If such devices proved the existence of multiple universes, then what were the theological implications - if a universe existed in which Iain Strachan were not saved (or as many in which I was saved as in which I wasn't saved, and a great many in which I didn't exist at all!) , then what would be the meaning of my faith, or indeed the lack of faith of the atheist version of me in another universe.

  It seems to me (but it may be because I don't really understand quantum computing) that there is a fallacy in this argument. In order for a quantum computing device to perform the huge number of parallel calculations, it must of necessity exist in all the parallel universes that are involved in the calculation. Furthermore, if we recall the principle that the flap of a butterfly's wings can (by chaos theory) "cause" tornadoes the other side of the world, then it would seem to me that the other universes in which that quantum computing device sat in the same point and had the "go" button pressed by the same person at the same time, must all share precisely the same history as the one we're in now. Whoever was saved in the one must be saved in all of them, because the slightest deviation would cause divergence of the behaviour of the system.

  Maybe this is too simplistic a view? Can someone enlighten me?

  Iain

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  After the game, the King and the pawn go back in the same box.

  - Italian Proverb
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Received on Thu Mar 2 20:57:30 2006