Applications of Chern-Simons Ward Identities to log(T\tau) Conductivity   Calculations of the nu=1/2 System
  We reconsider the theory of the half-filled Landau level with impurities using the Chern-Simons formulation and study Ward identities for the Chern-Simons theory. From these we get conductivity diagrams with impurities which obey the continuity equation. We calculate the conductivity of these diagrams for which we obtain log(T\tau) divergent conductivity diagrams for low temperature T. We compare our result with the experimental values of the low temperature conductivities. Finally we calculate the conductivity for small deviations of the magnetic field B from the value nu=1/2. In this case we get a singularity in the conductivity. 
Juergen Dietel