Memory formation is emerging as a new and productive theme for organizing our understanding of matter and functionality. While the notion of memory originates in the biological world in our conscious recollection of the past, other — often more subtle — forms of memory appear throughout phenomena encountered in chemistry, physics, and geophysics. In biology too, memory is a useful concept not just in our cognitive world but to describe the mechanics of cells and evolutionary training. Memory thus encompasses a broad set of phenomena built from non-equilibrium conditions. Thus, for example, memory of initial conditions is often stored in many material properties and some of these may possibly be recovered at later times. In condensed phases, it is often encountered in samples displaying hysteresis, both thermodynamic and mechanical, in the aging and rejuvenation of macromolecules, gels and glasses, in the response to external mechanical perturbations (cyclic memory), and in the memory of the particle shape in colloidal systems.
This special issue of JCP aims to contribute to the description of the most recent advances on this topic, and to help develop unifying viewpoints to understand memory effects in matter. The special issue will include experimental and theoretical/simulation-based papers. Because the science surrounding the origin of memory is evolving rapidly, the list of topics below is not complete. We hope that this list spurs more thoughts about how different physical and biological phenomena can be related to, and we hope productively understood, in terms of memory formation.
Guest Editors: Murugappan Muthukumar, Sidney R. Nagel, Srikanth Sastry, and Zorana Zeravcic, with JCP Editors Francesco Sciortino and David Reichman