Causal set theory

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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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  • #2
atyy
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Is this related to Sorkin's work?
 
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Yes, Sorkin founded it
 
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What counts as an "event" (when you are describing quantum fields)?
 
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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.
 
  • #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.
 
  • #7
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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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