Strongly Correlated Topological Superconductors and Topological Phase   Transitions via Green's Function
  We propose several topological order parameters expressed in terms of Green's function at zero frequency for topological superconductors, which generalizes the previous work for interacting insulators. The coefficient in topological field theory is expressed in terms of zero frequency Green's function. We also study topological phase transition beyond noninteracting limit in this zero frequency Green's function approach. 
Zhong Wang and Shou-Cheng Zhang
cond-mat.str-el