Characterization of MIPS in a suspension of repulsive Active Brownian Particles through dynamical features

Abstract

The two-dimensional Active Brownian Particles system is meant to be composed of hard disks, that show excluded volume interactions, usually simulated via molecular dynamics using pure repulsive potentials. We show that the softness of the chosen potential plays a role in the result of the simulation, focusing on the case of the emergence of Motility Induced Phase Separation. In a pure hard-sphere system with no traslational diffusion,the phase diagram should be completely determined by their density and Péclet number. However, we have found two additional effects that affect the phase diagram in the ABP model we simulate: the relative strength of the traslational diffusion compared to the propulsion term and the overlapping of the particles. As we show, the second effect can be strongly mitigated if we use, instead of the standard Weeks-Chandler- Andersen potential, a harder one, the pseudo-hard spheres potential. Moreover, in determining the boundary of our phase space, we have tried different approaches to detect MIPS and concluded that observing dynamical features, via the non-Gaussian parameter, is more efficient than observing structural ones, via the local density distribution function. We also demonstrate that the Vogel-Fulcher equation successfully reproduces the decay of the diffusion as a function of density, except for very high density cases. Thus, the ABP system behaves similarly to a fragile glass in this regard.

References in corpus (9)

• Theoretical perspective on the glass transition and amorphous materials
• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation
• Active matter
• Nonequilibrium equation of state in suspensions of active colloids
• Light Activated Self-Propelled Colloids
• Light-switchable propulsion of active particles with reversible interactions
• How active forces influence nonequilibrium glass transitions
• Phase behaviour and dynamical features of a two-dimensional binary mixture of active/passive spherical particles
• Static Structure of Active Brownian Hard Disks

Cited by in corpus (17)

• Role of rotational inertia for collective phenomena in active matter
• Active phase separation: new phenomenology from non-equilibrium physics
• Dynamics of active particles with translational and rotational inertia
• Active Brownian Particles in Random and Porous Environments
• Simulating active agents under confinement with Dissipative Particles (hydro)Dynamics
• Dynamical anomalies and structural features of Active Brownian Particles characterised by two repulsive length scales
• Anisotropic run-and-tumble-turn dynamics
• Inhomogeneous entropy production in active crystals with point imperfections
• Re-entrant percolation in active Brownian hard disks
• Active crystallization from power functional theory
• Polarization and dynamic phases of aligning active matter in periodic obstacle arrays
• Geometric and Nonequilibrium Criticality in Run-and-Tumble Particles with Competing Motility and Attraction
• Active wetting transitions induced by rotational noise at solid interfaces
• Dynamic path dependence of phase behaviors in dense active system
• Dynamics and rupture of doped Motility Induced Phase Peparation
• Effective interactions in active Brownian particles
• Kinetic Event-Chain Algorithm for Active Matter