TiMe · Exploring time-dependent memory effects in matter with viscoelastic snap-through of strips.

Memory is crucial in living organisms and computers, but is also a hallmark of complex materials such as crumpled paper, glasses or sheared foams. Memory manifests itself in a stunning variety, and is central both in fundamental research and for applications (ageing, adaptive matter, programmable matter). A new picture based on novel theoretical concepts, related to the pathways of transitions between metastable states recently appeared, and lead to a flurry of activity. But so far, this work focused mostly on quasistatic memory effects, where the duration of the input does not matter. Yet, time-dependent memory effects are encountered in many complex systems, and their microscopic origin is often unclear. I therefore propose to study time-dependent memory and pathways in a model mechanical system, explicitly tailored to exhibit time-dependent memory, while allowing direct observations and manipulations. Specifically, I will use viscoelastic thin strips that can toggle via a snap-through instability between two states as a basic building block to create systems with emergent time-dependent memory. This project provides the key to experimentally probe and reveal the mechanisms of time-dependent memory in matter, as well as to design and create systems with complex programmable pathways. I divide my project in three work packages:WP1. First, I will study the snapping of viscoelastic strips, that will constitute the basic elements of this model system.WP2. Next, I will assemble several of these strips to monitor the emergence of time-dependent memory effects and study both theirglobal aspects and pathways of transitions.WP3.Finally, I will aim to control time-dependent memory and design complex systems with predefined pathways.Leveraging the versatility and experimental accessibility of model mechanical In this project, I propose to use instabilities in viscoelastic strips to explore, understand and control the emergence of time dependent memory effects in matter.