UNIVERSALITY IN ISING-LIKE PHASE-TRANSITIONS OF LATTICES OF COUPLED CHAOTIC MAPS

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 d ata supports the existence of a new universality class, which groups t ogether phase transitions of synchronously updated models with Ising s ymmetry, irrespective of the specific microscopic evolution rule, and of the presence of stochastic noise. However, nonequilibrium, Ising-li ke phase transitions of asynchronously updated models belong to the Is ing universality class. The new universality class differs from the eq uilibrium Ising universality class by the value of the correlation len gth exponent, nu = 0.89 +/- 0.02, while exponent ratios beta/nu and ga mma/nu as well as Binder's cumulant U assume their usual value.