Abstract:
We discuss and compare two popular methods used for analyzing fluctuations in the number of active agents: the approach of Martin, Siggia, and Rose, usually connected with the Langevin-equation description of fluctuation kinetics, and the approach of Doi, directly related to the master-equation description of stochastic birth–death processes.
Keywords:renormalization group, reaction kinetics, random sink, random source, dimensional analysis, effective action.