Hydrodynamic origins of odd viscosity in spinner monolayers

Breaking parity and time-reversal in fluids allows to couple deformations to orthogonal stresses. This phenomenon translates into odd continuum material constants such as Hall viscosity.

While the continuum limit is well understood, in real systems odd viscosity arises from microscopic interactions between fluid constituents.

We combine simulations and analytical calculations of rotating particles in Stokes flow to show how odd responses can emerge from viscous hydrodynamic interactions in spinner monolayers.