Critical exponents of nonequilibrium, Ising-like phase transitions in two-dimensional lattices of locally coupled chaotic maps are estimated numerically using equilibrium finite-size scaling theory. Numerical data supports the existence of a new universality class, which groups together phase transitions of synchronously updated models with Ising symmetry, irrespective of the specific microscopic evolution rule, and of the presence of stochastic noise. However, nonequilibrium, Ising-like phase transitions of asynchronously updated models belong to the Ising universality class. The new universality class differs from the equilibrium Ising universality class by the value of the correlation length exponent, ν=0.89±0.02, while exponent ratios Β/ν and γ/ν as well as Binder's cumulant ${\mathrm{U}}^{\mathrm{*}}$ assume their usual value.

• Received 28 October 1996

DOI:https://doi.org/10.1103/PhysRevE.55.2606