Synchronization and partial synchronization of linear maps

We study synchronization of low-dimensional (d=2,3,4) chaotic piecewise linear maps that are coupled bidirectionally. For Bernoulli maps we find Lyapunov exponents and locate the synchronization transition, which numerically is found to be discontinuous (despite continuously vanishing Lyapunov exponent(s)). For tent maps, a limit of stability of the synchronized state is used to locate the synchronization transition that numerically is found to be continuous. For nonidentical tent maps at the partial synchronization transition, the probability distribution of the synchronization error is shown to develop highly singular behavior. We suggest that for nonidentical Bernoulli maps (and perhaps some other discontinuous maps) partial synchronization is merely a smooth crossover rather than a well-defined transition. More subtle analysis in the d=4 case locates the point where the synchronized state becomes stable. In some cases, however, a riddled basin attractor appears, and synchronized and chaotic behaviors coexist.