https://doi.org/10.1140/epjb/e2006-00029-9
Stochastic resonance and scale invariance in nonequilibrium metastable states
1
Department of Physics, Boston University, Boston, Massachusetts 02215, USA
2
Laboratoire des Colloïdes,
Verres et Nanomatériaux, Université Montpellier II, Montpellier 34095,
France
3
Instituto “Carlos I" de Física Teórica y Computacional, and
Depto. de Electromagnetismo y Física de la Materia, Universidad de Granada, 18071-Granada, España
Corresponding author: a phurtado@onsager.ugr.es
Received:
10
October
2005
Revised:
25
November
2005
Published online:
31
January
2006
Using computer simulations, we study metastability in a two-dimensional Ising ferromagnet relaxing toward a nonequilibrium steady state. The interplay between thermal and nonequilibrium fluctuations induces resonant and scale-invariant phenomena not observed in equilibrium. In particular, we measure noise-enhanced stability of the metastable state in a nonequilibrium environment. The limit of metastability, or pseudospinodal separating the metastable regime from the unstable one, exhibits reentrant behavior as a function of temperature for strong nonequilibrium conditions. Furthermore, when subject to both open boundaries and nonequilibrium fluctuations, the metastable system decays via well-defined avalanches. These exhibit power-law size and lifetime distributions, resembling the scale-free avalanche dynamics observed in real magnets and other complex systems. We expect some of these results to be verifiable in actual (impure) specimens.
PACS: 64.60.My – metastable phases / 05.70.Ln – Nonequilibrium and irreversible thermodynamics / 64.60.Qb – nucleation / 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006