A perspective on active glassy dynamics in biological systems

Abstract

AbstractDynamics is central to living systems. Many experiments in the last two decades have revealed glassy dynamics in diverse biological systems, showing a transition between a solid-like and a fluid-like state. The biological systems have nontrivial characteristics: they are active with novel control parameters and immense complexity. Moreover, glassiness in these systems has many nontrivial features, such as the behavior of dynamical heterogeneity and readily found sub-Arrhenius relaxation dynamics. Theoretical treatments of these systems are generally challenging due to their nonequilibrium nature and large number of control parameters. We first discuss the primary characteristics of a glassy system and then review the experiments that started this field and simulations that have led to a deeper understanding. We also show that despite many challenges in these systems, it has been possible to develop theories that have played a significant role in unifying diverse phenomena and bringing insights. The field is at the interface of physics and biology, freely borrowing tools from both disciplines. We first discuss the known equilibrium scenario and then present the primary changes under activity.