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Witten on spacetime

  1. Jun 12, 2014 #1
    I found an now historical article of witten speaking about the fate of spacetime, and I wanted to share it with you.

    Here it goes:
    http://www.sns.ias.edu/~witten/papers/Reflections.pdf [Broken]

    I hope you enjoy it
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Jun 14, 2014 #2
    Thanks! Somewhere I have buried a photocopy of this paper.
  4. Jun 15, 2014 #3
    I think it is paradoxical that Witten thought that string theory was going to change the way we think about space time, but at the end string theory is background dependent (at least in its current formulation*)

    *It should be noted that, in spite of what I've said above, I have several reasons (mainly coming from dualities, holography, Matrix String Theory and String Field Theory) to believe that a background independent formulation of string theory is possible.
  5. Jun 15, 2014 #4


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    It is in the book "Physics Meets Philosophy at the Planck Scale".

    I think Witten has always been well aware of the need for a background independent quantization of gravity (perhaps unlike a lot of stringy people lower down in the hierarchy). I think a while back there had been a kind of feeling that once the infinities of perturbative quantum gravity were tamed, the conceptual difficulties would some how fall in place...

    But along the way they may have found things that indicate the need to revise notions of spacetime.
    Last edited: Jun 15, 2014
  6. Jun 16, 2014 #5
    Is twistor theory Background Independent?
  7. Jun 16, 2014 #6


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    I think twistor theory is only partially background independent in that the emphasis is shifted away from the metric description to an abstract mathematical space (twistor space) however the twistor description retains the information about the light cone or conformal structure of space-time. As Penrose envisaged it, the light cone structure is fixed while the other degrees freedom are subject to quantum fluctuations.

    I think, possibly, there was some point in the 1980's that Witten favoured twister theory to provide the most promising way of formulating a background independent theory of strings, but he found that a lot of the nice features of twistor theory that hold in 4 dimensions dont extend to higher dimensions and so abandoned it.
  8. Jun 20, 2014 #7


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    I wonder how this article would look like now, almost twenty years later :)
  9. Jun 21, 2014 #8
    Twistor: Many thanks for the article!
    Very interesting the link between the usual four dimensional space time and the two dimensional conformal field theory.
  10. Jun 22, 2014 #9
    If you liked the article you may also like:

    http://www.sns.ias.edu/~witten/papers/duality.pdf [Broken]
    http://www.sns.ias.edu/~witten/papers/mmm.pdf [Broken]
    http://www.sns.ias.edu/~witten/papers/Holes.pdf [Broken]
    http://www.sns.ias.edu/~witten/papers/Mass.pdf [Broken]
    http://www.sns.ias.edu/~witten/papers/higgs.pdf [Broken] (before the discovery of the Higgs boson)
    http://www.sns.ias.edu/~witten/papers/string.pdf [Broken] *
    http://www.sns.ias.edu/~witten/papers/CurrentScienceVol81.pdf [Broken]
    http://www.sns.ias.edu/~witten/papers/BlackHoles.pdf [Broken]
    http://www.sns.ias.edu/~witten/papers/Symmetry.pdf [Broken] *
    http://www.sns.ias.edu/~witten/papers/Unravelling.pdf [Broken] *
    http://www.sns.ias.edu/~witten/papers/KnotsandPhysics.pdf [Broken] *

    *most accesible
    Last edited by a moderator: May 6, 2017
  11. Jun 23, 2014 #10
    I wonder, what are Witten´s current views on spacetime in the context of string/M Theory?
  12. Jun 24, 2014 #11
    Does he still believe that spacetime is emergent?
  13. Jun 28, 2014 #12
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