title: Distinguishing between discreteness effects in stochastic reaction processes.
abstract: The effect of discreteness on stochastic dynamics of chemically reacting systems is studied analytically. We apply the scheme bridging the chemical master equation and the chemical Fokker-Planck equation by a parameter representing the degree of discreteness previously proposed by the author for two concrete systems. One is an autocatalytic reaction system, and the other is a branching-annihilation reaction system. It is revealed that the change in characteristic time scales when discreteness is decreased is yielded between the two systems for different reasons. In the former system, it originates from the boundaries where one of the chemical species is zero, whereas in the latter system, it is due to modification of the most probable extinction path caused by discreteness loss.
authors.affiliation: Department of Planetology, Graduate School of Science, Kobe University, 1-1, Rokkodaicho, Nada, Kobe 657-8501, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Haruna