A mobility based approach to transport in chiral fluids

TL;DR

This paper investigates the microscopic origins of unique transport phenomena in chiral fluids, revealing how strong chirality causes reversed density wakes and explains effects like negative mobility and enhanced diffusion.

Contribution

It introduces a mobility-based nonequilibrium approach to explain the physical mechanisms behind transport phenomena in chiral fluids, emphasizing the role of odd mobility.

Findings

Reversed density wake caused by strong chirality.

Structural inversion explains negative mobility and enhanced diffusion.

Phenomena are robust across different interaction potentials.

Abstract

Chiral fluids, for which the mobility tensor has antisymmetric, off-diagonal components, exhibit transport phenomena absent in conventional systems, including interaction-enhanced diffusion and negative mobility. While these effects have been predicted theoretically and observed in simulations, their microscopic origin has remained unclear. Here, we address this question using a mobility-based nonequilibrium approach, analysing the steady-state drift of a tracer driven through an interacting chiral fluid. We show that, under strong chirality, the tracer generates a reversed density wake, in which regions of particle accumulation and depletion are inverted compared to the achiral case. This structural inversion of the wake provides a unified physical mechanism underlying both enhanced diffusion and negative mobility. Furthermore, we demonstrate that these phenomena are robust to changes in the interaction potential, highlighting their generality as a consequence of odd mobility.