Correlations and Fluctuations of Coherent Wave Transmission through Disordered Media

The correlation functions of the transmission coefficients for scalar wave propagation through disordered media are calculated by use of both diagrammatic techniques and numerical simulations. The calculation is valid in the diffusive regime: multiple elastic scattering with negligible absorption or inelastic scattering and a scattering length much longer than the wavelength. In addition to the familiar large local intensity fluctuations we find a novel memory effect and long-range correlations in the transmission coefficients which decay to a positive background value. Implications for light-scattering experiments are discussed.