Semiclassical theory of Coulomb anomaly
Levitov L.S., Shytov A.V.
An effective action approach for the problem of Coulomb blocking of tunneling is discussed. The method is applied to the strong coupling problem arising near zero bias, where perturbation theory diverges. We find an instant on for the electrodynamics in imaginary time, and express the anomaly through exact conductivity of the system σ(ω} q) and exact interaction, PACS: 72.10.Bg, 73.50.-h