Fig. 4.

Time autocorrelation of interaction shear stress and effective tissue viscosity. (A) Time autocorrelation function of the mean interaction shear stress for $P_0=3.45$ at various $v_0$. (B and D) Heat maps of the correlation time ${\tau }_m$ (B) and of the effective viscosity (D). The red crosses denote the liquid–solid phase transition boundary determined by $q=3.813$. The white region corresponds to regions where correlation time ${\tau }_m$ and effective viscosity ${\eta }_{\mathrm{𝑒𝑓𝑓}}$ diverge. Note that these regions largely coincide with the solid regime. (C) The effective viscosity as a function of $P_0$ at various $v_0$. The dashed lines correspond to the critical $P_0$ where the liquid–solid phase transition occurs. All results are for $100$ cells, $D_r=1$, and $T=\mathrm{40,000}$ with periodic boundary condition.