A random first-order transition theory for an active glass

作者：Nandi Saroj Kumar^*; Mandal Rituparno; Bhuyan Pranab Jyoti; Dasgupta Chandan; Rao Madan; Gov Nir S

来源：Proceedings of the National Academy of Sciences, 2018, 115(30): 7688-7693.

DOI：10.1073/pnas.1721324115

• active RFOT
• dense self-propelled particle system
• active glass
• persistence time
• fragility

How does nonequilibrium activity modify the approach to a glass? This is an important question, since many experiments reveal the near-glassy nature of the cell interior, remodeled by activity. However, different simulations of dense assemblies of active particles, parametrized by a self-propulsion force, f(0), and persistence time, tau(p), appear to make contradictory predictions about the influence of activity on characteristic features of glass, such as fragility. This calls for a broad conceptual framework to understand active glasses; here, we extend the random first-order transition (RFOT) theory to a dense assembly of self-propelled particles. We compute the active contribution to the configurational entropy through an effective model of a single particle in a caging potential. This simple active extension of RFOT provides excellent quantitative fits to existing simulation results. We find that whereas f(0) always inhibits glassiness, the effect of tau(p) is more subtle and depends on the microscopic details of activity. In doing so, the theory automatically resolves the apparent contradiction between the simulation models. The theory also makes several testable predictions, which we verify by both existing and new simulation data, and should be viewed as a step toward a more rigorous analytical treatment of active glass.

• 出版日期2018-7-24