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

TL;DR

This paper investigates a two-dimensional chiral fluid model with spinning colloids, revealing phase separation, interface phenomena, and edge currents, and connects microscopic mechanics with macroscopic chiral hydrodynamics.

Contribution

It introduces a thermodynamic framework for phase coexistence in chiral fluids and links microscopic edge currents to macroscopic rotational viscosity.

Findings

Phase separation between chiral liquid and dilute gas.

Surface tension influences interface corrections and edge currents.

Chirality induces dense rotating hexatic patches.

Abstract

We study a model chiral fluid in two dimensions composed of Brownian disks interacting via a Lennard-Jones potential and a non-conservative transverse force, mimicking colloids spinning at a rate $\omega$. The system exhibits a phase separation between a chiral liquid and a dilute gas phase that can be characterized using a thermodynamic framework. We compute the equations of state and show that the surface tension controls interface corrections to the coexisting pressure predicted from the equal-area construction. Transverse forces increase surface tension and generate edge currents at the liquid-gas interface. The analysis of these currents shows that the rotational viscosity introduced in chiral hydrodynamics is consistent with microscopic bulk mechanical measurements. Chirality can also break the solid phase, giving rise to a dense fluid made of rotating hexatic patches. Our work paves the way for the development of the statistical mechanics of chiral particles assemblies.