Driven Widom-Rowlinson lattice gas

Area of Science:

• Statistical Mechanics
• Soft Matter Physics
• Computational Physics

Background:

• The Widom-Rowlinson lattice gas is an athermal system with two particle species (A, B) exhibiting phase transitions driven by entropy.
• Previous studies on driven lattice gases, like the Katz-Lebowitz-Spohn (KLS) model, show unique collective behaviors and domain structures parallel to the drive.

Purpose of the Study:

• To investigate the effects of an external drive on the Widom-Rowlinson lattice gas.
• To analyze emergent phenomena, including domain formation, interface properties, and phase transitions under driving forces.

Main Methods:

• Utilized Monte Carlo simulations to model particle-hole exchange dynamics.
• Imposed a directional drive biasing particle movement.
• Analyzed structure factors, correlation functions, and defined a novel order parameter for multistripe states.

Main Results:

• Observed ordering into multiple striped domains oriented perpendicular to the drive, with a density and drive-dependent wavelength.
• Structure factors exhibit kink singularities (|q|), and correlation functions oscillate.
• Interfacial regions between domains remain statistically rough, contrasting with the KLS model where drives suppress roughness.

Conclusions:

• The driven Widom-Rowlinson lattice gas displays distinct collective behavior compared to other driven lattice models.
• A novel phase diagram in the density-drive plane is established, indicating the emergence of multistripe states.
• Preliminary evidence suggests the existence of a critical phase in this driven system.