Figure 9.

The self propulsion parameters, P and T , play a crucial role in defining the collective behavior of the monolayer. Flow fields V (x) are shown for long (a: T = 50min) and short (c: T = 1.25min) memory duration of cell polarity. The remaining parameters are the same as in Fig. 7. Flow fields are presented as in Fig. 8. The corresponding parallel and perpendicular velocity profiles are shown in panels (e) and (f), respectively. Increasing T results in wider, longer and faster streams. Similar, but less dramatic tendencies are seen when changing P (panels g and h). For large enough T, the system organizes into a phase where the correlation length is comparable to the system size. Movement within the monolayer is diffusive in the streaming regime as the average neighbor separation vs cell displacement curves (panels b and d) are consistent with the asymptotic behavior of Eq. (5), shown as the solid line. In the globally ordered (rotating) regime cells move further without separating. The asterisk marks the parameter values used in Fig. 7.