Classical Topological Order in Abelian and Non-Abelian Generalized   Height Models
  We present Monte Carlo simulations on a new class of lattice models in which the degrees of freedom are elements of an abelian or non-abelian finite symmetry group G, placed on directed edges of a two-dimensional lattice. The plaquette group product is constrained to be the group identity. In contrast to discrete gauge models (but similar to past work on height models) only elements of symmetry-related subsets S of G are allowed on edges. These models have topological sectors labeled by group products along topologically non-trivial loops. Measurement of relative sector probabilities and the distribution of distance between defect pairs are done to characterize the types of order (topological or quasi-LRO) exhibited by these models. We present particular models in which fully local non-abelian constraints lead to global topological liquid properties. 
R. Zach Lamberty, Stefanos Papanikolaou, Christopher L. Henley
cond-mat.stat-mech