Chaoslike behavior in nonchaotic systems at finite computation precision -art. no. 046310

The dynamical behavior of a two-dimensional map is investigated numerically . A chaoslike behavior, i.e., a nonsmooth distribution of the attractor and seemly sensitive dependence of the motion on initial condition is found as the system state is nonchaotic (both Lyapunov exponents are nonpositive). The key point for this strange behavior is that the mode corresponding to t he second negative Lyapunov exponent contains positive local Lyapunov expon ent segments. It is argued that this kind of behavior may be typical and ea sily observed in practical numerical computations and experiments where sma ll noise is inevitable.