Spatiotemporal dynamics of a self-propelled system with opposing alignment and repulsive forces

Area of Science:

• Condensed Matter Physics
• Statistical Mechanics
• Complex Systems

Background:

• Active matter systems exhibit emergent behaviors driven by self-propelled particles.
• Confined geometries introduce boundary effects influencing collective dynamics.
• Understanding interplay between alignment and repulsion is crucial for active matter.

Purpose of the Study:

• To investigate the effect of concurrent alignment and repulsion in confined active matter.
• To identify and characterize different dynamic phases and spatial patterns.
• To analyze synchronization phenomena and emergent collective behaviors.

Main Methods:

• Utilized a modified force-based Vicsek model for simulating confined active matter.
• Analyzed particle dynamics through alteration of alignment and repulsive force parameters.
• Employed correlation functions, chaos detection techniques, and Hilbert transform for analysis.

Main Results:

• Identified three distinct phases: random (low alignment), milling (mid-range alignment), and oscillatory (high alignment).
• The milling phase exhibited spatial patterns including ring-shaped mills and hybrid ring-cluster structures.
• Detected a weak chimera state, particularly in the ringed milling state, with coexisting synchronized and desynchronized oscillators.

Conclusions:

• Concurrent alignment and repulsion in confined active matter lead to rich phase behavior and spatial organization.
• The study reveals complex dynamics, including periodicity and chaos, correlating with alignment strength.
• A novel weak chimera state was identified, highlighting unique synchronization properties in structured active matter.