Fig. 3: Reconstructed attractor geometries and symbolic dynamics.

a–c Reconstructed attractor geometries by a method of delay from the measured time traces at \({I}_{{\rm{dc}}}\) = 12.6, 13.2, and 14.0 mA, respectively. The white plane is arbitrarily chosen Poincaré surface of section (see Methods). (Inset) Poincaré maps at the surfaces. The red dashed lines indicate a simple partition to divide the plane into two regions, \({R}_{{\rm{A}}}\) and \({R}_{{\rm{B}}}\), for encoding symbols, A and B. The Poincaré surface of section and partitions are identical for all \({I}_{{\rm{dc}}}\) in these figures. d–f Dynamics of symbols defined from the partition on the Poincaré' maps. Above the graphs, corresponding \(pn\) patterns and generated bit sequences are represented. The bits are defined as 0 \(\equiv\) [A,A,A,B,B,B] and 1 \(\equiv\) [A,B,B,B]. g–i Rules of the symbolic dynamics at \({I}_{{\rm{dc}}}\) = 12.6, 13.2, and 14.0 mA. j Generated bit sequences for long term at \({I}_{{\rm{dc}}}\) = 12.6, 13.2, and 14.0 mA.