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Is string theory deterministic?

  1. Mar 13, 2008 #1
    Is string theory deterministic?

    So if a supernatural mind knows all the physical information in the universe at a specific moment then he will exactly know (using string theory) what will happen in the future.

    If string theory is not deterministic, should the Theory of Every Thing be a deterministic one?
     
  2. jcsd
  3. Mar 13, 2008 #2
    I am very much not the best person to answer this question, but:

    My understanding is that string theory is a quantum theory, and that means it is not deterministic.

    There is a theory of "classical strings"-- remember, strings are just vibrating 1D objects-- which would (since it is classical) be deterministic. However to my knowledge classical string theory is not used in physics. As far as I know it is used just in textbooks to introduce students to the subject, and also as a building block to derive quantum string theory from.

    (As an aside: There exist philosophical complications to the claim, as I make above, that "quantum theories are not deterministic". It is possible to create deterministic quantum theories by the use of "hidden variables". For example the "Bohm interpretation" of quantum mechanics uses hidden variables and so is deterministic, in the sense that a "universe sysadmin" with access to the hidden variables could use that knowledge to calculate as you say "what would happen in future". However hidden variable quantum theories have their practical difficulties-- for one thing, they must be nonlocal theories-- and hidden variable theories are not widely used or considered as useful that I have seen. In particular I have never seen anyone attempt to apply hidden-variable interpretation to string theory.)
     
    Last edited: Mar 13, 2008
  4. Mar 14, 2008 #3
    So as I understood that a final theory or "The theory of Every Thing" may not be deterministic, so humans may reach in the future a theory explains every thing about the universe, but still that theory have indeterministic nature.
     
  5. Mar 14, 2008 #4

    Demystifier

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    Science Advisor

    Then see
    http://xxx.lanl.gov/abs/hep-th/0512186
    http://xxx.lanl.gov/abs/hep-th/0605250
    http://xxx.lanl.gov/abs/hep-th/0702060
    http://xxx.lanl.gov/abs/0705.3542

    You also said that "hidden variable quantum theories have their practical difficulties-- for one thing, they must be nonlocal theories". Well, due to certain dualities, string theory also has some nonlocal features. This, indeed, is used as one of the arguments (in one of the papers above) for the relation between string theory and Bohmian mechanics.

    See also
    https://www.physicsforums.com/showthread.php?t=220745
     
    Last edited: Mar 14, 2008
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