Interdependent superconducting networks

Cascades are self-amplifying processes triggered by feedback mechanisms that may cause a substantial part of a macroscopic system to change its phase in response to a relatively small local event. The theoretical background for these phenomena is rich and interdisciplinary, with interdependent networks providing a versatile framework to study their multiscale evolution. However, laboratory experiments aimed at validating this ever-growing volume of predictions have not been accomplished, mostly because of the lack of a physical mechanism that realizes interdependent couplings. Here we demonstrate an experimental realization of an interdependent system as a multilayer network of two disordered superconductors separated by an electric insulating film. We show that Joule heating effects due to large driving currents act as dependency links between the superconducting layers, igniting overheating cascades via adaptive and heterogeneous back-and-forth electrothermal feedback. We characterize the phase diagram of mutual superconductive transitions and spontaneous microscopic critical processes that physically realize interdependent percolation and generalize it beyond structural dismantling. This work establishes a laboratory manifestation of the theory of interdependent systems, enabling experimental studies to control and to further develop the multiscale phenomena of complex interdependent materials.