Dynamical density functional theory for dense odd-diffusive fluids

TL;DR

This paper develops a dynamical density functional theory for dense fluids with odd diffusion, revealing unique circulating currents and faster relaxation pathways, confirmed by simulations.

Contribution

The authors introduce a novel DDFT framework for odd-diffusive fluids, capturing nontrivial transport phenomena and collective behaviors in dense systems.

Findings

Odd diffusion creates circulating currents in bulk fluids.

Confinement induces angular density redistribution during relaxation.

The theory matches Brownian dynamics simulations quantitatively.

Abstract

Odd diffusion breaks time-reversal symmetry in overdamped systems through transverse probability currents while preserving equilibrium steady states. In this work, we develop a dynamical density functional theory (DDFT) for dense interacting odd-diffusive fluids and apply it to ultrasoft particles in two dimensions. In bulk, odd diffusion qualitatively reshapes collective relaxation by generating transient circulating current patterns which do not exist in normal fluids. Under harmonic ring confinement, the circulation of probability current induces an angular redistribution of density along the ring during relaxation. This unique footprint of odd diffusion opens up a shorter pathway to equilibrium. Repulsive interactions significantly enhance these effects. Excellent agreement with Brownian dynamics simulations confirms that our odd-DDFT framework quantitatively captures all essential nonequilibrium aspects of the nontrivial odd transport and collective redistribution for dense fluids in both bulk and confined geometries.