I have a basic understanding of how gravitational degrees of freedom are modelled in loop quantum gravity, but as far as I know, the main machinery - spin network states and observables, does not encode the matter degrees of freedom. My question is simply: How is matter currently modelled in loop quantum gravity?

Edit: Actually, the question applies not only to matter as in fermionic matter, but also the other three forces. The LQG spin networks are based around the SU2 symmetry of Ashtekar's gauge description of gravity - how do they incorporate the other gauge groups?

This post imported from StackExchange Physics at 2014-03-22 17:03 (UCT), posted by SE-user twistor59