Equation of state for the edge flow of chiral colloidal fluids

TL;DR

This paper derives an equation of state linking edge flow fluxes to bulk properties in chiral colloidal fluids, revealing differences between passive and active systems.

Contribution

It introduces an equation of state for edge flows in chiral colloidal fluids, connecting interface currents to bulk observables and contrasting passive and active origins.

Findings

Edge flux equals average odd stress in confined fluids.

Edge flux equals odd stress jump in phase-separated systems.

The equation of state distinguishes passive from active edge currents.

Abstract

We explore the edge flows that emerge at boundaries in nonequilibrium passive and active chiral colloidal fluids. We show that these complex interface currents obey an equation of state that relates their fluxes to bulk observables. For confined fluids, the edge flux is given by the average odd stress in the fluid. In phase-separated systems, the flux along the interface is given by the jump of the odd stress across the interface. We then use the equation of state to reveal, and contrast, the microscopic origins of the edge currents in passive and active systems.