Diffusive regimes in a two-dimensional chiral fluid

Abstract

Diffusion is a fundamental aspect of transport processes in biological systems, and thus, in the development of life itself. And yet, the diffusive dynamics of active fluids with directed rotation, known as chiral fluids, has not been analyzed in detail so far. Here, we describe the diffusive regimes of a two-dimensional chiral fluid, composed in this case of a set of identical disk-shaped rotors. We found strong experimental evidence of odd diffusion. This odd diffusion emerges in the form of a two-dimensional tensor with an antisymmetric part. In particular, we show that chiral diffusion is complex, featuring transitions between super, quasi-normal, and sub diffusion, and very slowly aging. Moreover, we show that the diffusion tensor elements, including off-diagonal elements; i.e., odd diffusion coefficient, change sign according to flow vorticity. Therefore, the chiral fluid has a self regulated diffusion, controlled by its vorticity.

Accepted in Communications Physics. 8 pages, 4 figures

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• Odd Diffusivity of Chiral Random Motion
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Cited by in corpus (8)

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• The Dance of Odd-Diffusive Particles: A Fourier Approach
• Spin and velocity correlations in a confined two-dimensional fluid of disk-shaped active rotors
• Mesoscale simulation model for odd fluids
• Phase separation in a chiral active fluid of inertial self-spinning disks
• Kinetic Theory of Chiral Active Disks: Odd Transport and Torque Density