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Q-deformed spin foam models of quantum gravity

  1. Apr 4, 2007 #1


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    For those who have been following my model, I see this as another step in the right direction.
    q-deformed spin foam models of quantum gravity
    Igor Khavkine and J. Daniel Christensen
    02 April 2007
    Large triangulations are necessary to approximate semiclassical space-times. The possibility of obtaining numerical results from larger triangulations takes us one step closer to that goal and increases the number of facets from which the physical properties of a spin foam model may be examined. As an example, we are able to study how the spin-spin correlation varies with the distance between faces in the triangulation.

    Consider a triangulated 4-manifold. Let _n denote the set of n-dimensional simplices of the triangulation. The dual 2-skeleton is formed by associating a dual vertex, edge and polygonal face to each 4-simplex, tetrahedron, and triangle of the triangulation, respectively.
    Given the discrete structure of our spacetime model, it is conceivable that this combinatorial distance, multiplied by a fundamental unit of length, approximates some notion of distance derived from the dynamical geometry of the spin foam model.
    (I use a double tetra. See my visuals)
  2. jcsd
  3. Apr 4, 2007 #2


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    Science Advisor
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    Dearly Missed

    You might be interested in Dan Chritensen's home page, if you haven't visited.

    He has a big list of useful links to LQG-related information.
    With his specialty in computing he also has some nice computer graphics, or did the last time I went there


    "...I am an associate professor in the Department of Mathematics at The University of Western Ontario in London, Ontario, with a cross appointment to the Department of Applied Mathematics, and an affiliation with the Perimeter Institute for Theoretical Physics.

    I enjoy hiking, rock climbing, kayaking and other outdoors sports. Here are photos from some trips I have been on.

    Contact information is below..."

    Here is his
    Information on spin foam models of quantum gravity
    (earlier title was: Spin networks, spin foams and loop quantum gravity)
    http://jdc.math.uwo.ca/spin-foams/index.html (need to scroll down to find the URLs)

    Their supercomputer is a Beowolf cluster.

    the QG group at Western (also known as UWO) consists of 4 researchers

    a postdoc named Josh Willis
    two PhD students named Igor Khavkine and Wade Cherrington.
    and I think they will have a fifth person soon (a PhD student of John Baez who is finishing thesis now and will move up there)

    Christensen has co-authored 3 papers with John Baez.

    Western seems like a good place for QG these days.
    Last edited: Apr 4, 2007
  4. Apr 4, 2007 #3


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    Well Marcus… you have made my day.
    I have never thought that the path that I was following was untrodded.
    Lo and behold up in the distance is a figure.
    Dan Christensen's home page
    Spin networks, spin foams and loop quantum gravity

    Spin Networks
    The applet below displays a small spin network

    Perhaps, he has missed observing some of the interesting points along the path, (a fundamental unit of length).
    I shall hurry forward and ask for an audience.
    Perhaps, he might be able to get “gregegan” to make a dynamic visual of my double tetra.

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