ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

SZFI SeminarLévay SáraWigner RCP SZFIInteracting jammed granular systems at 
the transition between two and three dimensionsTuesday, 23 November 2021, 
10:00, Bldg 1., auditorium, 
https://wigner-hu.zoom.us/j/92885697708?pwd=ZEVqQVhUOXVyV2dNNHZTL1pUMFdnUT09  
 Meeting ID: 928 8569 7708  Passcode: 376864Optimal 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. Minden érdeklődőt 
szívesen látunk! - Everyone is welcome to attend.Róbert 
Juhászsem-admin AT szfki.hu