Diffusive regimes in a two-dimensional chiral fluid

Abstract We have found strong experimental evidence of odd diffusion in a chiral fluid (composed in this case of a set of identical disk-shaped rotors); i.e., in general — but not always— the chiral fluid displays strong anisotropic diffusion, represented here by an antisymmetric two-dimensional tensor. In particular, we show that chiral diffusion is strikingly 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 the flow vorticity value. Therefore, the chiral fluid appears to have a self regulated diffusive behavior, controlled by chiral vorticity.