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The Computational universe

  1. Feb 17, 2005 #1

    wolram

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    http://lanl.arxiv.org/pdf/quant-ph/0501135
    The Computational Universe
    A theory of quantum gravity based on quantum computation
    24 jan 2005
     
  2. jcsd
  3. Feb 17, 2005 #2

    marcus

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    I know :smile:
    that is Seth Lloyd's new paper. I posted a link to it the day it came out
    https://www.physicsforums.com/showthread.php?p=439912#post439912
    and one of us, Kea, responded
    I commented briefly on Seth Lloyd in that 24 jan post, looked up his past work in Quantum Computing and put a link to a 1996 article. Not long after that, Kea recommended the same article to SetAI, in a thread he started which became a sticky. The Seth Lloyd article seems to appeal to SetAI----and Kea's comment suggests to me that there could be a bunch of people interested in the idea of modeling gravity with computation
     
    Last edited: Feb 17, 2005
  4. Feb 17, 2005 #3

    wolram

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    Sorry i missed it, it is rather mechanical approach to QG, which
    has some appeal to me, but i guess it will stay on the book shelf,
    shame really i like furry little quib its.
     
  5. Feb 17, 2005 #4

    marcus

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    May I invite you to also take a look at the article I flagged right after that one (25 January) here
    https://www.physicsforums.com/showpost.php?p=440989&postcount=290

    Reconstructing Quantum Geometry from Quantum Information: Spin Networks as Harmonic Oscillators
    Florian Girelli, Etera R. Livine
    16 pages, revtex, 3 figures

    "Loop Quantum Gravity defines the quantum states of space geometry as spin networks and describes their evolution in time. We reformulate spin networks in terms of harmonic oscillators and show how the holographic degrees of freedom of the theory are described as matrix models. This allow us to make a link with non-commutative geometry and to look at the issue of the semi-classical limit of LQG from a new perspective. This work is thought as part of a bigger project of describing quantum geometry in quantum information terms."

    Instead of being put off by not understanding it, try to get the drift. Here is a quote:

    ----quote from Livine Girelli---
    A possibly relevant point of view is provided by quantum information. It appears that many mathematical tools and physical questions are actually shared by loop quantum gravity and the quantum information field, and it could be helpful to develop an explicit bridge between these two research areas. This defines a project to reformulate quantum geometry in terms of entropy, entanglement and quantum reference frames. The present work is thought as part of this bigger project. We seek to understand the geometry of spin networks at the kinematical level. We reformulate spin networks in terms of harmonic oscillators and we show how the boundary degrees of freedom in LQG are described as matrix models.....
    ... In a last section, we explain how quantum reference frames should allow us to localize systems on a spin network background and end with the idea that a notion of distance could be constructed on a spin network can be constructed in terms of entanglement between parts of that spin network.
    ---end quote---

    I think Livine Girelli hit a rich vein here.
     
  6. Feb 17, 2005 #5

    selfAdjoint

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    This is where Kea points out to us that categories and toposes are the natural way to express those common tools and physical relations. True, too.
     
  7. Feb 17, 2005 #6

    wolram

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    I must admit the idea of spin network, circuits is an interesting
    concept, the information is probably in the papers you pointed
    to, but im to green, and can not see how these spin networks
    circuits evolve and multiply, and if they follow a blueprint or
    form spontaneously.
    My printer is dead so i have book marked these pages for hope
    of better understanding.
     
  8. Feb 17, 2005 #7
    If space-time is a result of a quantum computer algorithms, and computer algorithms have entropy (I've been told), does this article imply that there is a certain emount of entropy associated with space-time itself? I think I've read other articles that may have directly said this, but I don't remember where.
     
  9. Feb 20, 2005 #8
    I like the idea of unify quantum gravity with computation. Maybe some of you know that I believe that the Universe is a creation of a computer (read my journal for more info). I have read Lloyd's paper superficially and I find interesting the idea of Computational graphs, that somehow remember to me an integrated circuit of some PC
     
  10. Feb 20, 2005 #9

    Kea

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    meteor

    Would you like to vote on selfAdjoint's poll in Quantum? Not that I'm trying to sway you either way.....well, it would be nice if enough people voted for a certain option then maybe we could get a new subforum one of these days...
     
  11. Feb 22, 2005 #10

    wolram

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    Science by proxy ? no
     
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