Self-Organized Stationary Patterns in Networks of Bistable Chemical Reactions

Experiments with networks of discrete reactive bistable electrochemical elements organized in regular and nonregular tree networks are presented to confirm an alternative to the Turing mechanism for the formation of self‐organized stationary patterns. The results show that the pattern formation can be described by the identification of domains that can be activated individually or in combinations. The method also enabled the localization of chemical reactions to network substructures and the identification of critical sites whose activation results in complete activation of the system. Although the experiments were performed with a specific nickel electrodissolution system, they reproduced all the salient dynamic behavior of a general network model with a single nonlinearity parameter. Thus, the considered pattern‐formation mechanism is very robust, and similar behavior can be expected in other natural or engineered networked systems that exhibit, at least locally, a treelike structure. Law and order: A classical example of self‐organization in chemical and biological systems is provided by the Turing instability. Now an alternative, potentially more common mechanism for the emergence of stationary patterns in complex networks has been explored by a combination of experiments and theory. Such patterns were found to emerge in networks of bistable elements by the pinning of spreading activation at critical nodes (see picture).