Memory Effects in Amorphous Mechanical Systems

Amorphous mechanical systems such as thin sheets crumpled into a soft ball, elastic foams and granular systems can exhibit a long-lasting Kovacs-like memory effect: a slow non-monotonic volume or stress relaxation, the shape of which contains information on mechanical perturbations applied to the system long before the measurement was taken. The talk will discuss previous and recent observations, and our attempts to uncover the mechanism underlying memory retention and related phenomena in these systems.