Mechanisms behind the irregular regime at strong chemotactic interactions

Identify the mechanisms that generate the irregular, potentially chaotic-like regime observed at very strong chemo-repulsive interactions (large Péclet numbers and large relative mobility) in the conserved active emulsion model defined by the dimensionless equations (Eqs. (8a–b)), and ascertain whether this regime represents a distinct dynamical phase or only a long transient.

Background

In numerical simulations, the authors observe that for very strong interactions (large Pe) the system exhibits highly mobile, irregularly shaped domains that continually merge and split, with little apparent order beyond high- and low-density segregation.

They note that in this regime the density can even exceed equilibrium plateau values, and while they suspect these behaviors may be transient, the underlying mechanisms remain to be clarified.