Relevant perturbations at the spin quantum Hall transition
  We study relevant perturbations at the spin quantum Hall critical point using a network model formulation. The model has been previously mapped to classical percolation on a square lattice, and we use the mapping to extract exact analytical values of the scaling dimensions of the relevant perturbations. We find that several perturbations that are distinct in the network model formulation correspond to the same operator in the percolation picture. We confirm our analytical results by comparing them with numerical simulations of the network model. 
S. Bhardwaj, I. A. Gruzberg, and V. Kagalovsky
cond-mat.dis-nn