Anomalous metastability in a temperature-driven transition

¹ IPCF- CNR, UOS Roma Kerberos and Dipartimento di Fisica, Università “La Sapienza” - Piazzale A. Moro 5, 00185 Roma, Italy
² Dipartimento di Matematica e Fisica, Università Roma Tre - Via della Vasca Navale 84, 00146 Roma, Italy
³ Istituto dei Sistemi Complessi - CNR - Via del Fosso del Cavaliere 100, 00133 Rome, Italy

Received: 15 April 2014
Accepted: 9 May 2014

Abstract

The Langer theory of metastability provides a description of the lifetime and properties of the metastable phase of the Ising model field-driven transition, describing the magnetic-field–driven transition in ferromagnets and the chemical-potential–driven transition of fluids. An immediate further step is to apply it to the study of a transition driven by the temperature, as the one exhibited by the two-dimensional Potts model. For this model, a study based on the analytical continuation of the free energy (Meunier J. L. and Morel A., Eur. Phys. J. B, 13 (2000) 341) predicts the anomalous vanishing of the metastable temperature range in the large-system-size limit, an issue that has been controversial since the eighties. By a GPU algorithm we compare the Monte Carlo dynamics with the theory. For temperatures close to the transition we obtain agreement and characterize the dependence on the system size, which is essentially different with respect to the Ising case. For smaller temperatures, we observe the onset of stationary states with non-Boltzmann statistics, not predicted by the theory.