Coupled catastrophes in systems with bidirectional feedback
Four distinct types of coupled catastrophes are possible in two systems with bidirectional feedback. The color codes the type of the fixed point, based on a linear stability analysis – a focus if the Jacobian has a complex pair of eigenvalues and a node if the eigenvalues are real. Stability follows, in the usual way, from the signs of the real parts of the eigenvalues.Catastrophes are present across many disciplines, ranging from the extinction of populations in ecosystems to the collapse of prices in financial systems. Here, we focus on how interactions between systems influence these catastrophes. Specifically, we study two bidirectionally coupled sub-systems—each of which possesses an S-shaped bifurcation curve with saddle-node bifurcations—and explore how interactions between them can lead to simultaneous bifurcations. There are four types of such coupled catastrophes – synchronization, anti-synchronization, consensus, and anti-consensus. Which of these behaviors manifests depends both the intrinsic dynamics of the subsystems and ways in which they are coupled. In general, there are three possible coupling classes – cooperation, competition, and predation. We develop an analytic/graphical methodology to determine and visualize the locus of the coupled catastrophes in parameter space, and we show which classes of couplings support different types of coupled catastrophes. Finally, we discuss several potential applications areas from distinct domains.