Figure 1

(a) The system consists of granular particles (light grains) confined between two rigid plates (dark grains) at constant pressure. The top plate is driven via a spring mechanism, where an extremum of the spring is attached to the plate and the other is pulled at constant velocity. See the supplementary materials available online for an animation of a slip event in the real and in the force space [20]. (b) Time evolution of the top plate position $X(t)$. The inset indicates that between two large slips there are many microslips. (c) Configuration of normal force network. Stronger forces correspond to thicker and darker lines. (d) Slip size distribution for slips and microslips.Reuse & Permissions

Figure 2

The top plate position in a slip event $X(t)$. The vertical dashed line indicates the unjamming time $t_u$. Inset: Top plate position for two system replicas, which evolve with $V_d=0$. The replica made at time $t_u$ remains in the jammed configuration (continuous line), whereas the one made at time $t_u+\delta t$ slips (dashed line).Reuse & Permissions

Figure 3

Time evolution of the top plate position (a) and of the correlation function of the normal forces $C^n(t,t_u)$ (b). Dashed lines identify the unjamming time $t_u$. The inset shows $C^n$ and $C^{\mathrm{tg}}$ across a microslip at $t=1579.5$.Reuse & Permissions

Figure 4

Correlation functions at the unjamming (upper panels) and at the subsequent jamming transition (lower panels). The left panels show the normal and tangential force correlation functions $C^{n,\mathrm{tg}}(t_0,t)$ (symbols) during a slip event. The dashed line shows the time evolution of the plate position scaled between 0 and 1. The plain lines show the self-scattering function $F(q,t)$ for $q=3$, 5, 9, 17. The corresponding ${\tau }_q$ are shown in the right panels. $t_0$ is fixed equal to $t_u$ for the unjamming transition, and to $t_0=1614$ for the subsequent jamming.Reuse & Permissions

Figure 5

Time evolution of the susceptibility ${\chi }_{\alpha }$ for different $\alpha$. (Inset) Size of a microslip $\Delta X$ versus the corresponding value ${\chi }_{\alpha }$. The straight line is ${\chi }_{\alpha }^b$, with $b\simeq 1.2$.Reuse & Permissions