Dynamical Density Functional Theory for Dense Odd-Diffusive Fluids.

Area of Science:

• Soft matter physics
• Non-equilibrium statistical mechanics
• Theoretical fluid dynamics

Background:

• Odd diffusion is a phenomenon that breaks time-reversal symmetry in overdamped systems.
• It involves transverse probability currents but maintains equilibrium steady states.
• Understanding its impact on dense fluids is crucial for non-equilibrium physics.

Purpose of the Study:

• To develop a dynamical density functional theory (DDFT) for densely interacting odd-diffusive fluids.
• To investigate the effects of odd diffusion on ultrasoft particles in two dimensions.
• To analyze collective relaxation and density redistribution under confinement.

Main Methods:

• Development of a novel odd-DDFT framework.
• Application to two-dimensional systems of ultrasoft particles.
• Comparison with Brownian dynamics simulations for validation.

Main Results:

• Odd diffusion qualitatively reshapes collective relaxation in bulk fluids by generating transient circulating currents.
• Under harmonic ring confinement, probability current circulation leads to angular density redistribution.
• Repulsive interactions significantly enhance these odd-diffusive effects.
• The odd-DDFT framework quantitatively captures non-equilibrium transport and redistribution.

Conclusions:

• The developed odd-DDFT provides a quantitative framework for studying non-trivial odd transport in dense fluids.
• Odd diffusion introduces unique dynamic behaviors, including circulating currents and altered relaxation pathways.
• These findings are relevant for understanding non-equilibrium phenomena in confined and interacting soft matter systems.