Velocity force curves, laning, and jamming for oppositely driven disk systems

Area of Science:

• Physics
• Complex Systems
• Statistical Mechanics

Background:

• Driven particle systems with quenched disorder, such as vortices in type-II superconductors, exhibit complex phase transitions.
• Understanding the behavior of multi-component particle systems under external forces is crucial for various fields.

Purpose of the Study:

• To investigate the phase behavior of a two-dimensional disk system with two species driven in opposite directions.
• To characterize the relationship between driving force, disk density, and emergent phases.
• To explore the connection between observed transitions and dynamical phase transitions in other driven systems.

Main Methods:

• Utilizing computational simulations to model a two-dimensional disk system.
• Measuring the average velocity of one species against the applied driving force.
• Analyzing system behavior as a function of drive and disk density.

Main Results:

• Identification of four distinct phases: jammed, phase separated, continuously mixing, and laning.
• Correlation of phase transitions with velocity-force curve jumps, mirroring phenomena in driven systems with disorder.
• Observation of negative differential mobility in some transitions, where velocity decreases with increasing drive.
• Demonstration of phase robustness against thermal fluctuations.

Conclusions:

• The study identifies robust phases and transitions in a driven two-species disk system.
• Observed transitions share similarities with dynamical phase transitions in disordered systems.
• Potential links to absorbing phase transitions are discussed, highlighting organization into states with lost dynamics.