
#1
Apr407, 10:47 AM

P: 640

For those who have been following my model, I see this as another step in the right direction.
http://arxiv.org/pdf/0704.0278 qdeformed spin foam models of quantum gravity Igor Khavkine and J. Daniel Christensen 02 April 2007 Large triangulations are necessary to approximate semiclassical spacetimes. 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 spinspin correlation varies with the distance between faces in the triangulation. Consider a triangulated 4manifold. Let _n denote the set of ndimensional simplices of the triangulation. The dual 2skeleton is formed by associating a dual vertex, edge and polygonal face to each 4simplex, 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) jal 



#2
Apr407, 11:32 AM

Astronomy
Sci Advisor
PF Gold
P: 22,808

You might be interested in Dan Chritensen's home page, if you haven't visited.
He has a big list of useful links to LQGrelated information. With his specialty in computing he also has some nice computer graphics, or did the last time I went there http://jdc.math.uwo.ca/ "...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/spinfoams/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 Dan 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 coauthored 3 papers with John Baez. Western seems like a good place for QG these days. 



#3
Apr407, 12:55 PM

P: 640

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. http://jdc.math.uwo.ca/ Dan Christensen's home page http://jdc.math.uwo.ca/spinfoams/index.html Spin networks, spin foams and loop quantum gravity http://gregegan.customer.netspace.ne...p.html#d16_4_1 http://gregegan.customer.netspace.ne...D/Spin/SN.html Spin Networks http://gregegan.customer.netspace.ne...Spin/Spin.html 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. jal 


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