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Do theories of quantum gravity require that space-time is a lattice?

  1. Apr 23, 2012 #1
    Do theories of quantum gravity require that space-time is a lattice instead of a continuum?

    I guess this question has been addressed elsewhere, but I would appreciate hearing different points of view. Please dummy down the responses so a philosopher can understand it.
     
  2. jcsd
  3. Apr 24, 2012 #2
    James, quantum gravity strongly implies a discrete spacetime. First, look at black hole thermodynamics. Specifically, a region has what is called a Bekenstein bound - a limit to the amount of information a region can contain, a maximum density. Trying to exceed this density will simply result in the growth of the event horizon around this region. Next, look at LQG, which is based purely around a dicrete spacetime, no question there. Finally, M-theroy also implies a discrete spacetime - without getting into detail, it breaks strings down into discrete 'string bits'. I see no possible way that spacetime couldn't be discrete on the planck scale.
     
  4. Apr 26, 2012 #3
    See IS SPACETIME QUANTIZED here:
    http://www.knowledgerush.com/kr/encyclopedia/Spacetime/

    A different perspective:
    http://arxiv.org/abs/1010.4354

    Interesting discussions in these forums:

    Good discussions here:
    https://www.physicsforums.com/showthread.php?t=391989

    https://www.physicsforums.com/showthread.php?p=3558771#post3558771
     
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