Yielding and memory in a driven mean-field model of glasses

Abstract: Glassy systems reveal a wide variety of generic behaviors inherited from their intrinsically-disordered, non-equilibrium nature. These include universal non-phononic vibrational spectra, and driven phenomena such as thermal and mechanical annealing, yielding transitions and memory formation, all linked to the underlying complex energy landscape of glasses. Yet, a unified theory of such diverse glassy phenomena is currently lacking. Here, we study a recently introduced mean-field model of glasses, shown to reproduce the universal non-phononic vibrational spectra of glasses, under oscillatory driving forces. We show that the driven mean-field model, admitting a Hamiltonian formulation in terms of a collection of random-stiffness anharmonic oscillators with disordered interactions, naturally predicts the salient dynamical phenomena in cyclically deformed glasses. Specifically, it features a yielding transition as a function of the amplitude of the oscillatory driving force, characterized by an absorbing-to-diffusive transition in the system's microscopic trajectories and large-scale hysteresis. The model also reveals dynamic slowing-down from both sides of the transition, as well as mechanical and thermal annealing effects that mirror their glass counterparts. We demonstrate a non-equilibrium ensemble equivalence between the driven post-yielding dynamics at fixed quenched disorder and quenched disorder averages of the non-driven system. Finally, mechanical memory formation is demonstrated, in which memories can be stored in the model and subsequently extracted. Overall, the mean-field model offers a theoretical framework that unifies a broad range of glassy behaviors.