Breakdown of universality in transitions to spatio-temporal chaos

Tomas Bohr, Martin van Hecke, Rene' Mikkelsen, Mads Ipsen

Published 2000-08-17, updated 2001-05-17Version 3

In this Letter we show that the transition from laminar to active behavior in extended chaotic systems can vary from a continuous transition in the universality class of Directed Percolation with infinitely many absorbing states to what appears as a first order transition. The latter occurs when {\em finite} lifetime non-chaotic structures, called ``solitons'', dominate the dynamics. We illustrate this scenario in an extension of the deterministic Chat\'e--Manneville coupled map lattice model and in a soliton including variant of the stochastic Domany-Kinzel cellular automaton.