Inter-particle forces in amorphous solids can be used to study phenomena such as jamming and force-chains in both athermal and thermal systems. In the athermal case (e.g. athermal glasses and colloids), we find the forces by expanding the force-laws in a Laurent-Taylor series of the particle distances. Particle positions and the pressure are all that is required [1] and the method is shown to accurately recover the force-law in simulation. In the thermal case, using mean positions, our method can predict an effective force-law [2] allowing for analysis of thermal systems using tools hitherto reserved for athermal ones, and thereby the study of stability, soft excitations etc. Quite remarkably we also observe the emergence of effective many-body interactions, even when the bare interactions are purely 2-body.

1. O. Gendelman, Y. G. Pollack and I. Procaccia, Phys. Rev. E. 93, 060601(R) (2016).

2. O. Gendelman, E. Lerner, Y.G. Pollack, I. Procaccia, C. Rainone and B. Riechers, submitted for publication, arXiv:1608.05919.

3. Presentation slides can be found at: http://physics.bgu.ac.il/~yoavpo/Athermal_and_Thermal_Force-law-presentation-IPS_2016.pdf