Active thermodynamics of inertial chiral active gases: equation of state and edge currents

TL;DR

This paper develops a thermodynamic framework for chiral active gases, deriving an equation of state, Fick's law with odd diffusion, and predicting edge currents that depend on chirality, supported by experimental verification.

Contribution

It introduces the first comprehensive active thermodynamics for chiral active gases, including novel equations of state and edge current predictions.

Findings

Derived an equation of state linking density and pressure with effective temperature.

Formulated Fick's law with a full diffusion matrix predicting odd diffusion.

Predicted edge currents at container walls that vary nonmonotonically with chirality.

Abstract

One of the most fundamental quests in the physics of active matter concerns the existence of a comprehensive theory for its macroscopic properties, i.e. an ``active thermodynamics''. Here, we derive and experimentally verify key elements of the active thermodynamics of ideal chiral active gases, unveiling edge currents and odd diffusivity as their peculiar features. Our main results are the derivation of an equation of state relating density and pressure via a chirality-dependent effective temperature, the derivation of Fick's law including the full diffusion matrix predicting odd diffusion, and the exact prediction of edge currents at container walls that nonmonotonically depend on chirality.