Phase Coexistence and Edge Currents in the Chiral Lennard-Jones Fluid

Area of Science:

• Statistical Mechanics
• Soft Matter Physics
• Fluid Dynamics

Background:

• Colloidal systems exhibit complex behaviors influenced by interparticle forces and external fields.
• Chiral hydrodynamics describes fluids with intrinsic angular momentum, relevant for active matter.
• Phase separation is a critical phenomenon in many-body systems, affecting material properties.

Purpose of the Study:

• To investigate phase separation in a 2D model chiral fluid composed of Brownian disks.
• To analyze the impact of Lennard-Jones potential and nonconservative transverse forces on fluid behavior.
• To establish a thermodynamic framework for characterizing chiral fluid phases and their properties.

Main Methods:

• Simulating a 2D system of Brownian disks with Lennard-Jones interactions and transverse forces.
• Employing a thermodynamic framework to analyze phase separation and equations of state.
• Calculating surface tension and interface corrections to coexisting pressure.
• Analyzing edge currents at the liquid-gas interface to determine rotational viscosity.

Main Results:

• The chiral fluid undergoes phase separation into a chiral liquid and a dilute gas phase.
• Surface tension, increased by transverse forces, affects interface corrections to pressure.
• Edge currents at the liquid-gas interface are generated, consistent with bulk rotational viscosity.
• Chirality can disrupt the solid phase, forming dense fluids of rotating hexatic patches.

Conclusions:

• The study provides a thermodynamic characterization of phase separation in chiral fluids.
• Microscopic measurements of rotational viscosity align with chiral hydrodynamics predictions.
• This work lays the foundation for the statistical mechanics of chiral particle assemblies.