Joseph Paulsen: 0000-0001-6048-456X

Document Type





memory formation, condensed matter physics, phase change materials, transient analysis, disordered magnets




Science and Engineering Research Board, University of Chicago, Simons Foundation, American Chemical Society Petroleum Research Fund, Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Department of Science and Technology, Ministry of Science and Technology


This review was inspired by a program at the Kavli Institute for Theoretical Physics in Santa Barbara that was held during the winter of 2018. We are grateful to Greg Huber at the KITP who helped shepherd the program in its early stages. S. R. N. and S. S. thank the other co-organizers of this program: Susan Coppersmith and Alan Middleton. We had wonderful discussions with the attendees of this program. In particular, we thank Itai Cohen, Leticia Cugliandolo, Karin Dahmen, Karen Daniels, Chandan Dasgupta, Greg Huber, Mehran Kardar, Yoav Lahini, Craig Maloney, Enzo Marinari, Muhittin Mungan, Arvind Murugan, Lev Truskinovsky, and Tom Witten for very useful and inspiring feedback on many of the ideas presented here. We are grateful to the KITP for its hospitality during this program, supported in part by NSF PHY-1748958. In addition, this work was supported by the NSF MRSEC Program DMR-1420709, NSF DMR-1404841, and DOE DE-FG02-03ER46088, and the Simons Foundation for the collaboration “Cracking the Glass Problem” Award No. 348125 at the University of Chicago (S. R. N.). J. D. P. acknowledges the donors of the American Chemical Society Petroleum Research Fund for partial support of this work. N. C. K. acknowledges support from NSF DMR-1708870. S. S. acknowledges support through the J. C. Bose Fellowship, SERB, DST, India.


Biology | Physics


Memory formation in matter is a theme of broad intellectual relevance; it sits at the interdisciplinary crossroads of physics, biology, chemistry, and computer science. Memory connotes the ability to encode, access, and erase signatures of past history in the state of a system. Once the system has completely relaxed to thermal equilibrium, it is no longer able to recall aspects of its evolution. The memory of initial conditions or previous training protocols will be lost. Thus many forms of memory are intrinsically tied to far-from-equilibrium behavior and to transient response to a perturbation. This general behavior arises in diverse contexts in condensed-matter physics and materials, including phase change memory, shape memory, echoes, memory effects in glasses, return-point memory in disordered magnets, as well as related contexts in computer science. Yet, as opposed to the situation in biology, there is currently no common categorization and description of the memory behavior that appears to be prevalent throughout condensed-matter systems. Here the focus is on material memories. The basic phenomenology of a few of the known behaviors that can be understood as constituting a memory will be described. The hope is that this will be a guide toward developing the unifying conceptual underpinnings for a broad understanding of memory effects that appear in materials.



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