Equilibrium fluctuations of Gradient reversible particle systems

Summary The Boltzmann-Gibbs principle is known to be crucial in the study of the fluctuations of interacting particle systems. A new method is proposed in this paper which confirms this principle for models with gradient reversible dynamics in equilibrium. The method is simpler and can be applied to more general models than the conventional one which is developed by Brox et al. To illustrate the idea in more detail, we study the weakly asymmetric simple exclusion process of which the jump rates are slowly varying. As a consequence of the Boltzmann-Gibbs principle, the limit of the density fluctuation fields is identified as a generalized Ornstein-Uhlenbeck process. Finally, the extension to models with long range interactions is briefly discussed.