On universality in aging ferromagnets

Christophe Chatelain (1)

1 LPM - Laboratoire de physique des matériaux

This work is a contribution to the study of universality in out-of-equilibrium lattice models undergoing a second-order phase transition at equilibrium. The experimental protocol that we have chosen is the following: the system is prepared in its high-temperature phase and then quenched at the critical temperature $T_c$. We investigated by mean of Monte Carlo simulations two quantities that are believed to take universal values: the exponent $\lambda/z$ obtained from the decay of autocorrelation functions and the asymptotic value $X_\infty$ of the fluctuation-dissipation ratio $X(t,s)$. This protocol was applied to the Ising model, the 3-state clock model and the 4-state Potts model on square, triangular and honeycomb lattices and to the Ashkin-Teller model at the point belonging at equilibrium to the 3-state Potts model universality class and to a multispin Ising model and the Baxter-Wu model both belonging to the 4-state Potts model universality class at equilibrium.

Mots clés: out-of-equilibrium processes; aging; universality; lattice models

Domaines: Mécanique statistique [cond-mat.stat-mech]

Christophe Chatelain. On universality in aging ferromagnets. Journal of Statistical Mechanics: Theory and Experiment, 2004, -, pp.P06006. ⟨10.1088/1742-5468/2004/06/P06006⟩. ⟨hal-00001399v2⟩