Off-equilibrium response function in coarsening systems

In the late stage dynamics of systems evolving via domain coarsening, the linear response function splits into the sum of a stationary term, due to thermal fluctuations within domains, and of an aging term due to off-equilibrium interface dynamics. The latter contribution is analyzed in the pure Ising model under variation of space dimensionality and in the random field Ising model in one dimension. The variety of behaviors observed can be accounted for in terms of the effective response associated to a single interface. Implications for the connection between static and dynamic properties are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.