The fluctuation-dissipation theorem and the linear Glauber model

M. O. Hase, S. R. Salinas, T. Tomé, M. J. de Oliveira

Published 2006-02-13, updated 2006-04-20Version 2

We obtain exact expressions for the two-time autocorrelation and response functions of the $d$-dimensional linear Glauber model. Although this linear model does not obey detailed balance in dimensions $d\geq 2$, we show that the usual form of the fluctuation-dissipation ratio still holds in the stationary regime. In the transient regime, we show the occurence of aging, with a special limit of the fluctuation-dissipation ratio, $X_{\infty}=1/2$, for a quench at the critical point.