Low frequency flicker noise has been argued to occur in spatially extended metastable systems near a critical point (Bak et al., 1987). An Ising-Glauber model based method is suggested here to systematically obtain temperature dependentnth-order correlation functions forNarbitrary interacting two-level systems (TLSs). This model is fully consistent with existing methods to calculate1/fnoise spectra from TLSs and complements them. However, with as such noa prioriassumptions on the typical log normal distribution of fluctuation rates, it is shown that1/fαnoise manifests in two different cases: first in the thermodynamic limit on a 2D lattice with long range antiferromagnetic interactions at low temperatures and second in the case of a statistical ensemble of finite-sized spin clusters representing disorder, but where each cluster is ordered due to ferromagnetic interactions.
Temperature dependence of the vibrational spectrum of porphycene: a qualitative failure of classical-nuclei molecular dynamics
