"Optical conductance fluctuations: diagrammatic analysis in Landauer approach and non-universal effects"

The optical conductance of a multiple scattering medium is the total transmitted light of a diffuse incoming beam. This quantity, very analogous to the electronic conductance, exhibits universal conductance fluctuations. We perform a detailed diagrammatic analysis of these fluctuations. With a Kadanoff-Baym technique all the leading diagrams are systematically generated. A cancellation of the short distance divergencies occurs, that yields a well behaved theory. The analytical form of the fluctuations is calculated and applied to optical systems. Absorption and internal reflections reduce the fluctuations significantly.