Intrinsic common noise in a system of two coupled Brusselators

We investigate effects of coupling two chemical subsystems through diffusion of chemical species. We consider the Langevin description of the actual microscopic dynamics and show that diffusive coupling gives rise to a common noise term along with the deterministic interaction. As a model example, we study two diffusively coupled Brusselator systems. By numerical Langevin simulations, we inspect the effect of the common noise term on the total correlation between the two Brusselators; we also verify the validity of the Langevin approach by comparison to simulations of the more accurate master equation. The intrinsic common noise has its strongest effect for the Brusselator dynamics operating at a stable fixed point far from the Hopf bifurcation; in this case, the common noise reduces the correlation of the Brusselators significantly. We also show that for specific parameter sets the covariance between the systems is maximized (or minimized) at a finite system size. (C) 2010 Elsevier B.V. All rights reserved.