Persistence at the onset of spatio-temporal intermittency in coupled map lattices

We study persistence in coupled circle map lattices at the onset of spatio-temporal intermittency, an onset which marks a continuous transition, in the universality class of directed percolation, to a unique absorbing state. We obtain a local persistence exponent of θl=1.49±0.02 at this transition, a value which closely matches values for θl obtained in stochastic models of directed percolation. This result constitutes suggestive evidence for the universality of persistence exponents at the directed percolation transition. Given that many experimental systems are modelled accurately by coupled map lattices, experimental measurements of this persistence exponent may be feasible