Minimal mechanism for flocking in phoretically interacting active particles
arXiv:2504.07050 · doi:10.1039/D5SM01005E
Abstract
Coherent collective motion is a widely observed phenomenon in active matter systems. Here, we report a flocking transition mechanism in a system of chemically interacting active colloidal particles sustained purely by chemo-repulsive torques at low to medium densities. The basic requirements to maintain the global polar order are excluded volume repulsions and long-ranged repulsive torques. This mechanism requires that the time scale individual colloids move a unit length to be dominant with respect to the time they deterministically respond to chemical gradients, or equivalently, pair colloids sliding together a minimal unit length before deterministically rotating away from each other. Switching on the translational repulsive forces renders the flock a crystalline structure. Furthermore, liquid flocks are observed for a range of chemo-attractive inter-particle forces. Various properties of these two distinct flocking phases are contrasted and discussed. We complement these results with stability analysis of a hydrodynamic model, which admits the transition corresponding to destabilization of the flocking state observed in particle-based simulations.
13 pages, 8 figures; to appear in Soft Matter
References in corpus (30)
- Novel type of phase transition in a system of self-driven particles
- Collective motion
- Emergence of macroscopic directed motion in populations of motile colloids
- Collective motion of self-propelled particles interacting without cohesion
- Clusters, asters and collective oscillations in chemotactic colloids
- Fluctuations and Pattern Formation in Self-Propelled Particles
- Dynamic clustering and chemotactic collapse of self-phoretic active particles
- Flow-induced phase separation of active particles is controlled by boundary conditions
- Active phase separation by turning toward regions of higher density
- A particle-field representation unifies paradigms in active matter
- Self-assembly of Active Colloidal Molecules with Dynamic Function
- Sounds and hydrodynamics of polar active fluids
- Which Interactions Dominate in Active Colloids?
- Chemotactic self-caging in active emulsions
- Flocking without alignment interactions in attractive active Brownian particles
- Self-propelled hard disks: implicit alignment and transition to collective motion
- Velocity alignment promotes motility-induced phase separation
- Self-Aligning Polar Active Matter
- Understanding Collective Dynamics of Soft Active Colloids by Binary Scattering
- Dry Active Matter exhibits a self-organized 'Cross Sea' Phase
- Emergent dynamics due to chemo-hydrodynamic self-interactions in active polymers
- Competing chemical and hydrodynamic interactions in autophoretic colloidal suspensions
- A new universality class describes Vicsek's flocking phase in physical dimensions
- Pattern formation and phase transition in the collective dynamics of a binary mixture of polar self-propelled particles
- Minimum scaling model and exact exponents for the Nambu-Goldstone modes in the Vicsek Model
- Minimal mechanism for flocking in phoretically interacting active particles
- Rigid flocks, undulatory gaits, and chiral foldamers in a chemically active polymer
- Fluctuating hydrodynamics of an autophoretic particle near a permeable interface
- Molecular chaos in dense active systems
- Collective dynamics and phase transition of active matter in presence of orientation adapters