Memory-Driven Self-Propulsion and Flocking of Chemically Active Droplets
arXiv:2607.14451
The paper presents a theory showing that delayed (memory) feedback in biochemical reactions can destabilize stationary droplets, causing them to become self‑propelled and to align into polar flocks and traveling patterns.
Abstract
Biomolecular condensates are continually remodeled by biochemical reactions that can exhibit non-Markovian, history-dependent dynamics. We develop a theory of active phase separation with non-Markovian reactions and show that delayed reaction feedback destabilizes stationary droplets: when the memory time becomes comparable to the reaction turnover time, condensates deform and spontaneously acquire a polar, self-propelled state. In multidroplet systems, persistent memory wakes mediate alignment, producing polar flocks and, at higher concentrations, traveling labyrinths. These results establish reaction memory as a control parameter of active phase separation, linking condensate remodeling, autonomous motility, and collective organization, and suggest a possible route to flocking-like behavior within cells.