We partition the perturbation phase space in the three-element discrete nonlinear Schrödinger equation into symmetric and antisymmetric subspaces. We then show that chaotic motion in the neighborhood of symmetric trajectories is confined to the antisymmetric space. Chaos occurs in the system at arbitrarily low levels of nonlinearity, in agreement with previous calculations. We call this phenomenon ‘‘microchaos.’’

• Received 16 February 1993

DOI:https://doi.org/10.1103/PhysRevA.48.3863