Aging processes in reversible diffusion-limited reactions

Reversible diffusion-limited reactions display anomalous (i.e. slow) dynamics characterized by a power-law relaxation toward stationarity. In contrast to previous studies that focused on the time-dependence of this relaxation, we study here the nonequilibrium behavior of various simple reversible reaction-diffusion models in the aging regime. Starting from the exact Langevin equations describing these models, we derive expressions for two-time autocorrelation and autoresponse functions and obtain a simple aging behavior for these quantities. The autoresponse function is thereby found to depend on the specific nature of the chosen perturbation of the system.