The microscopic origin of abrupt transitions in interdependent systems

Phase transitions are fundamental features of statistical physics. While the well-studied continuous phase transitions are known to be controlled by external $\mathit{\text{macroscopic}}$ changes in the order parameter, the origin of abrupt transitions is not yet clear. Here we show that abrupt phase transitions may occur due to a unique internal $\mathit{\text{microscopic}}$ cascading mechanism, resulting from dependency interactions. We experimentally unveil the underlying mechanism of the abrupt transition in interdependent superconducting networks to be governed by a unique metastable state of a long-living resistance cascading plateau. This plateau is characterized by spontaneous $\mathit{\text{microscopic}}$ changes that last for $\mathit{\text{thousands}}$ of seconds, followed by a $\mathit{\text{macroscopic}}$ phase shift of the system. Similar microscopic mechanisms are expected to be found in a variety of systems showing abrupt transitions.