Collective behaviors of self-propelled particles with tunable alignment angles

Area of Science:

• Physics
• Soft Matter Physics
• Complex Systems

Background:

• Active matter systems, such as self-propelled rods, exhibit collective behaviors driven by self-propulsion and alignment interactions.
• Nematic alignment rules govern the orientational order in many active matter systems.
• Frustration in interactions can lead to novel emergent phenomena in physical systems.

Purpose of the Study:

• To develop and investigate an aligning active matter model with tunable alignment angles.
• To explore the effects of frustration introduced by nonvanishing alignment angles on collective behavior.
• To compare the phenomenology of this new model with the standard self-propelled rods model.

Main Methods:

• Agent-based microscopic simulations of cone-shaped particles with tunable collision angles.
• Linear stability analysis of a continuum description derived from the Boltzmann approach.
• Analysis of collective behaviors including band formation and orientational order.

Main Results:

• The model exhibits distinct phenomenology compared to standard self-propelled rods.
• Antiparallel bands are observed in an intermediate parameter range, indicating novel collective motion.
• Frustration introduced by many-body interactions destabilizes homogeneous nematic order across a wide range of alignment angles.

Conclusions:

• Tunable alignment angles in active matter models lead to significantly different collective behaviors.
• The presence of frustration is a key factor in destabilizing nematic order and promoting new patterns.
• The developed model provides a framework for studying complex interactions and emergent phenomena in active matter.