Growing length and time scales in activity-mediated glassy dynamics in confluent cell monolayers.

Abstract

Activity-mediated unjamming of a confluent glassy system is crucial for several biological processes, such as embryogenesis and cancer metastasis. During these processes, the cells progressively change their junction properties, characterized by an interaction parameter p_{0}, and become motile. Here, we study the effect of nonequilibrium active fluctuations, in the form of self-propulsion, on the glassy dynamics in a confluent system. We simulate the active vertex model and use the analytical mode-coupling theory (MCT) to show that the nature of the transition in the presence of activity remains similar to that in a thermal system where the fluctuations are temperaturelike. The agreement of the simulation results with the MCT predictions demonstrates that the structure-dynamics feedback mechanism controls the relaxation dynamics. In addition, we present the first computation of a dynamic length scale, ξ_{d}, in confluent systems using finite-size scaling, and show that the growing relaxation time exhibit a power-law dependence on ξ_{d}. Furthermore, unlike particulate glasses, the static length that governs the finite-size scaling of the relaxation time is proportional to ξ_{d}, revealing the unique nature of the glassy dynamics in confluent systems.