  We propose a microscopic hamiltonian together with a master equation
description to model stochastic hierarchical Random Telegraph Signal (RTS) or
Pop-corn noise in nano-junctions. The microscopic model incorporates the
crucial Coulomb correlations due to the trapped charges inside the junction or
at the metal-oxide interface. The exact solution of the microscopic model is
based on a generalization of the Nozieres-De Dominicis method devised to treat
the problem of the edge singularity in the X-ray absorption and emission
spectra of metals. In the master equation description, the experimentally
accessible transition rates are expressed in terms of the exact multi-channel
Scattering matrix of the microscopic hamiltonian.
