Communication: broken-ergodicity and the emergence of solid behaviour in amorphous materials.

Using a combination of theory and molecular dynamics simulations, we show how solid behaviour emerges in amorphous materials from microscopic considerations. The effect on the systems response to a sudden change in strain, upon entering the history dependent glass state, is focused on. An important symmetry that is always present in a fluid state, is shown to be broken for a simulated history dependent amorphous solid. Details of how this applies to a single sample and an ensemble of independent samples are discussed, along with the dependence on the time scale the system is monitored on.