John Baez

Lecture at Non Perturbative Quantum Gravity: Loops and Spin Foams

May 4, 2004

Spin Foam Models

A "spin foam" is a higher-dimensional analogue of a Feynman diagram where instead of a graph we use a higher-dimensional complex with vertices, edges and faces. Loop quantum gravity gives an interesting picture of the quantum geometry of space, and spin foam models seek to supplement this with a picture of the quantum geometry of spacetime. Here we summarize results of both analytical work and extensive computer calculations in two spin foam models: the Barrett-Crane models of Riemannian and Lorentzian quantum gravity in 3+1 dimensions.

You can see the slides here:

• Spin Foam Models - PDF or Postscript

For more on this subject try these papers:

• Carlo Rovelli, Loop Quantum Gravity.

• John Baez, Spin Foam Models.

• John Baez, An Introduction to Spin Foam Models of BF Theory and Quantum Gravity.

• John Baez and John Barrett, Integrability for Relativistic Spin Networks.

• John Baez, J. Daniel Christensen, Thomas Halford and David Tsang, Spin Foam Models of Riemannian Quantum Gravity.

• John Baez, J. Daniel Christensen and Greg Egan, Asymptotics of 10j Symbols

You can also see photos of the conference where I gave this talk!

I also wrote an issue of This Week's Finds about this conference: week206.

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