2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/17583We present a general relation between Mandel's $Q$ parameter describing variance of number of photons emitted from a single molecule and a three time correlation function describing a spectral diffusion process the molecule is undergoing. For a prototype of such a stochastic process an exact solution is found which exhibits rich types of physical behaviors.Statistical MechanicsMesoscale and Nanoscale Physicstext