Cumulant-based formulation of higher-order fluorescence correlation spectroscopy

Extended derivations regarding the cumulant-based formulation of higher-order fluorescence correlation spectroscopy (FCS) are presented. First, we review multivariate cumulants and their relation to photon counting distributions in single and multi-detector experiments. Then we derive the factorized correlation functions which describe system of diffusing and reacting molecules using two independent approaches. Finally, we calculate the variance of these correlation functions up to the fourth order.