Granular and amorphous solids are a condensed form of matter which show elastic response but lack periodic structure. In our group we use simulations and theory to try to explain different aspects of these materials with emphasis on an irreversibility transition which we have recently discovered. We have shown that the transition stems from a “transition to chaos” and have also studied its connection to the depinning transition which is a non-equilibrium phase transition. However, there are many open questions that still exist in this research topic and are related to the nature of the non-equilibrium phase transition and issues concerning ergodicity and entropy production which we are still studying.

Displacement of particles during an avalanche

Phase diagram for the

depinning transition

Glasses have a complex potential energy landscape

Transition from periodic to chaotic behavior

Amorphous solids are disordered