Interaction-Induced Memories Reveal the Complexity of Disordered Matter
Memory effects probe the complexity of disordered matter and its fundamental constituents and interactions. While models based on independent elements capture generic memories, interactions are predicted to produce many interaction-induced memories which so far have been observed in artificial systems only. Here we reveal that archetypical disordered materials - polycrystalline alloys, crumpled sheets, and steel wool - store multiple memories that strengthen with repeated cycling - in stark contrast to predictions for non-interacting systems. Interacting-based models capture our observations and predict a cascade of interaction-induced memory motifs, including the dominant one observed here. Our results reveal hitherto hidden complexity in disordered media, opening a fresh route towards the observation, modeling and utilization of interaction-induced memories, including for in-materia computing.