Remarks on vacuum fluctuations around a spinning cosmic string
  We apply the point-splitting method to investigate vacuum fluctuations in the nonglobally hyperbolic background of a spinning cosmic string. Implementing renormalization by removing the Minkowski contribution it is shown that although the Green function in the literature satisfies the usual Green function equation, it leads to pathological physical results. 
V.A. De Lorenci and E.S. Moreira, Jr. (EFEI-Itajuba')