Előadó: Lévay Sára

Előadás címe: Interacting jammed granular systems at the transition between two and three dimensions

Dátum: 2021. november 23., 10:00

Helyszín: 1-es épület Tanácsterem, illetve online: https://wigner-hu.zoom.us/j/92885697708?pwd=ZEVqQVhUOXVyV2dNNHZTL1pUMFdnUT09 Meeting ID: 928 8569 7708 Passcode: 376864

Optimal packings of uniform spheres are solved in two and three dimensions. The main difference between them is that the two-dimensional ground state can be easily achieved by simple dynamical processes, while in three dimensions this is impossible due to the fact that the locally optimal tetrahedral configuration is not space-filling. The question arises: What can one expect in a system which is at the transition between two and three dimensions? My talk aims to answer this question by presenting experimental and numerical results of a narrow system filled with monodisperse spherical particles, subjected to shaking. I will show that this system behaves neither as a two-dimensional nor as a three-dimensional system: The globally optimal configuration is optimal in the local sense as well, but due to orientational frustration it is difficult to reach. Furthermore, this system is a good candidate to study the applicability of Edwards theory. More than 30 years ago Edwards proposed an ensemble of equiprobable jammed states using equilibrium statistical physics to describe granular packings. By applying the Edwards ensemble to our narrow system we could give the analytical formulation of the partition function. I will show that the observables can be calculated exactly and the calculation matches reasonably well with simulations. This allows us to test Edwards theory on a coupled system of two subsystems with different properties. This will be the focus of the second part of my talk.