Glass Transition and Jamming

Many works have contributed to clarify similarities and differences between these two transitions. Jamming is geometric in nature, while the glass transition is a thermodynamic transition of "quasi-equilibrium». In a glass, the molecules vibrate around their equilibrium positions, which form a disordered network.There are a very large number of these networks and therefore possible glasses.When the glass is formed, it is possible to continue to compress it and / or to decrease its temperature. At zero temperature and at "infinite" pressure, the molecules overlap and the system is in a jammed state.

We study these phenomena in vibrated granular packings. Despite the non-equilibrium nature of these forced dissipative systems, they behave from a structural and dynamic point of view in a way very similar to a hard disk liquid. Beyond a certain pressure, they form a glass - in the sense that the particles are trapped by the cages formed by their neighbors. And, if they are further compressed, the particles form permanent contacts and the pressure diverges; this is jamming.

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