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Why are stings only one dimension?

  1. Jun 9, 2013 #1
    Why are strings only one dimension?

    Why is the fundamental particle a one dimensional string as opposed to,for example, a three dimensional ball that oscillates?
     
    Last edited: Jun 9, 2013
  2. jcsd
  3. Jun 9, 2013 #2

    phinds

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    Answer that and I predict a Nobel Prize for you.
     
  4. Jun 9, 2013 #3
    Hm. I'm highly uneducated on the matter but it seems to me that with one dimensional string you could build more complex and convoluted abstractions including a sphere as a posed to a bunch of little spheres rotating to reach the same goal but with less accuracy.
     
  5. Jun 10, 2013 #4
    But nowadays string theory is no longer just a theory of string, there are extended objects like branes.
     
  6. Jun 10, 2013 #5
    From Green, Schwarz and Witten's book on String theory:

    "Membranes and objects of still higher dimensionality have another glaring problem, as follows. Eq (the action for such objects) defines a n+1 dimensional quantum field theory, which by power counting is renormalizable for n = 1 and unrenormalizable for n > 1. Making sense of Eq() as a quantum theory is as hard as making sense of general relativity as a quantum theory. Thus membranes and higher dimensional objects would hardly be a promising start toward quantum gravity"

    There are other reasons for it too, outlined in that same book next to this quote (it's on page 60). So it's not arbitrary, and we have some ideas why it might be that way, but as far as I know they're all technical. You can imagine though that strings "spread out" interactions, avoiding the kinds of divergences you get in QFT.
     
    Last edited: Jun 10, 2013
  7. Jun 12, 2013 #6
    Nobody knows if the fundamental particles are strings or not. String theory is still very much hypothetical.
     
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