On the lifetime of excited states of frustration model of spin glasses

An analysis of the low energy excited states of the ± J model of Ising spins on a square lattice is developped in terms of clustering of solidary spins. Two types of clusters are exhibited : entropic and pinned clusters regarding the occurence of potential barriers in the relaxation. The mean reversal time of these clusters is determined and interpreted as one dimensional random walk in phase space. The size dependence of this mean reversal time varies as n² (n denoting the number of spins in the cluster) or $\text{n}{}^2\text{x exp(?}\text{ΔE}\text{k}{}_{\mathrm{B}}\text{T}\text{)}$ where ΔE is the potential barrier, instead of n in the case of ferromagnetic Ising model.