Proposal and applications of a method for the study of irreversible phase transitions

ERNESTO S. LOSCAR; NARA GUISONI; EZEQUIEL V. ALBANO

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

APS - American Physical Society

Año: 2009 vol. 80 p. 511231 - 511235

1063-651X

The gradient method for the study of irreversible phase transitions in far-from-equilibrium lattice systems is proposed and successfully applied to both the archetypical case of the Ziff-Gulani-Barshad (ZGB) model (R.M. Ziff et al., Phys. Rev. Lett. 56, 2553 (1986)) and a forest-fire cellular automaton. By setting a  gradient of the control parameter along one axis of the lattice, one can simultaneously treat both the active and the inactive phases of the system. In this way different interfaces are defined whose study allows us to find the active-inactive phase transition (both of first and second order), as well as the description of the active phase as composed of two further phases: the percolating and the nonpercolating ones. The average location and the width of the interfaces obey standard scaling behavior that is essentially governed by the roughness exponent alpha=1/(1+u), where u is the suitable correlation length exponent.