Universal properties of repulsive self-propelled particles and attractive driven particles

Abstract

Motility-induced phase separation (MIPS) is a nonequilibrium phase separation that has a different origin from equilibrium phase separation induced by attractive interactions. Similarities and differences in collective behaviors between these two types of phase separation have been intensely discussed. Here, to study another kind of similarity between MIPS and attraction-induced phase separation under a nonequilibrium condition, we perform simulations of active Brownian particles with uniaxially anisotropic self-propulsion (uniaxial ABPs) in two dimensions. We find that (i) long-range density correlation appears in the homogeneous state, (ii) anisotropic particle configuration appears in MIPS, where the anisotropy removes the possibility of microphase separation suggested for isotropic ABPs [X.-Q. Shi et al., Phys. Rev. Lett. 125, 168001 (2020)], and (iii) critical phenomena for the anisotropic MIPS presumably belong to the universality class for two-dimensional uniaxial ferromagnets with dipolar long-range interactions. Properties (i)-(iii) are common to the well-studied randomly driven lattice gas (RDLG), which is a particle model that undergoes phase separation by attractive interactions under external driving forces, suggesting that the origin of phase separation is not essential for macroscopic behaviors of uniaxial ABPs and RDLG. Based on the observations in uniaxial ABPs, we construct a coarse-grained Langevin model, which shows properties (i)-(iii) and corroborates the generality of the findings.

10+9 pages

References in corpus (7)

• Motility-Induced Phase Separation
• Phase transition in the collective migration of tissue cells: experiment and model
• Traffic jams, gliders, and bands in the quest for collective motion
• Molecular-scale substrate anisotropy and crowding drive long-range nematic order of cell monolayers
• Aspects of the density field in an active nematic
• Short-time Behaviour and Criticality of Driven Lattice Gases
• On the universal Gaussian behavior of Driven Lattice Gases at short-times

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• Hermitian and non-Hermitian topology in active matter
• Bubble formation in active binary mixture model
• Defect-Mediated Aggregation and Motility-Induced Phase Separation in Self-Propelled Lattice-Gas Active XY Model
• Superdiffusion and antidiffusion in an aligned active suspension