Topological Quantum Error Correction with Optimal Encoding Rate
  We prove the existence of topological quantum error correcting codes with encoding rates $k/n$ asymptotically approaching the maximum possible value. Explicit constructions of these topological codes are presented using surfaces of arbitrary genus. We find a class of regular toric codes that are optimal. For physical implementations, we present planar topological codes. 
H. Bombin, M.A. Martin-Delgado