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Causal set theory

  1. May 14, 2009 #1
    Anyone heard of causal set theory before? Basically, it is a concept that our universe should be viewed solely as set of discrete events and the causal relations between them. I wrote a thesis where I described the Lagrangians of quantum fields. Please let me know what you think: arXiv:0905.2263
     
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  3. May 14, 2009 #2

    atyy

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    Is this related to Sorkin's work?
     
  4. May 14, 2009 #3
    Yes, Sorkin founded it
     
  5. May 14, 2009 #4
    What counts as an "event" (when you are describing quantum fields)?
     
  6. May 15, 2009 #5
    Every point of space time is referred to as event. The only reason there are finitely many "events" is that I assume that there are only finitely many points in space time; they just are spaced so densely that they look continuous to us.

    By the way, when I say "spaced so densely", it is not a well defined term since there is nothing "between" these points (after all, spacetime=points). So, according to causal set theory, spacetime, by its nature, is discrete, and its discrete elements are called events.
     
  7. May 16, 2009 #6

    atyy

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    How is a continuum derived from discrete elements?

    I've heard Xiao-Gang Wen say something similar, like the fundamental elements are spins or qbits with nothing between them. But I think when he talks about the low energy limit, that assumes some sort of fixed smooth background to define low energy.
     
  8. May 16, 2009 #7
    Thinking of the Milne spacetime, it seems like it would be difficult for the density of a discrete spacetime not to produce a preferred frame?

    (I'm not really disagreeing with the discrete approaches, just wondering if you could explain it a little more?)
     
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