Spin-glass dynamics: experiment, theory and simulation

TL;DR

This review synthesizes experimental, theoretical, and simulation studies of spin-glass dynamics, highlighting recent advances in understanding complex behaviors like memory, rejuvenation, and temperature chaos through precise measurements and models.

Contribution

It provides a comprehensive convergence of experimental and numerical results, clarifying the physics of spin-glass phenomena and proposing directions for future research.

Findings

Experimental measurements of coherence lengths approaching macroscopic scales

Numerical reproduction of memory and rejuvenation effects

Insights into temperature chaos and off-equilibrium dynamics

Abstract

The study of spin-glass dynamics, long considered the paradigmatic complex system, has reached important milestones. The availability of single crystals has allowed the experimental measurement of spin-glass coherence lengths of almost macroscopic dimensions, while the advent of special-purpose computers enables dynamical simulations that approach experimental scales. This review provides an account of the quantitative convergence of these two avenues of research, with precise experimental measurements of the expected scaling laws and numerical reproduction of classic experimental results, such as memory and rejuvenation. The article opens with a brief review of the defining spin-glass properties, randomness and frustration, and their experimental consequences. These apparently simple characteristics are shown to generate rich and complex physics. Models are introduced that enable quantitative dynamical descriptions. After a summary of the main numerical results in equilibrium, paying particular attention to temperature chaos, this review examines off-equilibrium dynamics in the absence of a magnetic field and shows how it can be related to equilibrium structures through the fluctuation-dissipation relations. The nonlinear response at a given temperature is then developed, including experiments and scaling in the vicinity of the transition temperature $T_\mathrm{g}$. The consequences of temperature change $\unicode{x2013}$including temperature chaos, rejuvenation, and memory$\unicode{x2013}$ are reviewed. The interpretation of these phenomena requires identifying several length scales relevant to dynamics, which, in turn, generate new insights. Finally, issues for future investigations are introduced, including what is to be nailed down theoretically, why the Ising Edwards-Anderson model is so successful at modeling spin-glass dynamics, and experiments yet to be undertaken.