Detecting topological order in a ground state wave function.

  title={Detecting topological order in a ground state wave function.},
  author={Michael A. Levin and Xiao-Gang Wen},
  journal={Physical review letters},
  volume={96 11},
A large class of topological orders can be understood and classified using the string-net condensation picture. These topological orders can be characterized by a set of data (N, di, F(lmn)(ijk), delta(ijk). We describe a way to detect this kind of topological order using only the ground state wave function. The method involves computing a quantity called the "topological entropy" which directly measures the total quantum dimension D= Sum(id2i). 
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