A group field theory for 3d quantum gravity coupled to a scalar field
  We present a new group field theory model, generalising the Boulatov model, which incorporates both 3-dimensional gravity and matter coupled to gravity. We show that the Feynman diagram amplitudes of this model are given by Riemannian quantum gravity spin foam amplitudes coupled to a scalar matter field. We briefly discuss the features of this model and its possible generalisations. 
Laurent Freidel, Daniele Oriti, James Ryan