*Yuliang Jin, Pierfrancesco Urbani, Francesco Zamponi, *Hajime Yoshino,

A stability-reversibility map unifies elasticity, plasticity, yielding and jamming in hard sphere glasses,

Science Advances 4, eaat6387 (2018).

[Summary] Amorphous solids, such as glasses, have complex responses to deformations, with significant consequences in material design and applications. In this respect two intertwined aspects are important: stability and reversibility. It is crucial to understand on the one hand how a glass may become unstable due to increased plasticity under shear deformations; on the other hand, to what extent the response is reversible, meaning how much a system is able to recover the original configuration once the perturbation is released. By focusing on dense assemblies of hard spheres as the simplest model of amorphous solids, we exhaustively map out the stability and reversibility of glass states under normal and shear strains, using extensive numerical simulations. The region on the normal-shear strain phase diagram where the original glass state remains solid is bounded by the shear-yielding and the shear-jamming lines which meet at a yielding-jamming crossover point. This solid phase can be further divided into two sub-phases: the stable glass phase where the system deforms purely elastically and is totally reversible, and the marginal glass phase where it experiences stochastic plastic deformations at mesoscopic scales and is partially irreversible. The details of the stability-reversibility map depend strongly on the quality of annealing of the glass. This study provides a unified framework for understanding elasticity, plasticity, yielding and jamming in amorphous solids.