Point particles in 2+1 dimensions: toward a semiclassical loop gravity   formulation
  We study point particles in 2+1 dimensional first order gravity using a triangulation to fix the connection and frame-field. The Hamiltonian is reduced to a boundary term which yields the total mass. The triangulation is dynamical with non-trivial transitions occurring when a particle meets an edge. This framework facilitates a description in terms of the loop gravity phase space. 
Jonathan Ziprick
gr-qc