Chirality in a system of active air-driven spinners*

We present an analysis (based on kinetic theory) of the rich phase behavior and dynamics that we have

observed in experiments with a fluid of disk-shaped rotors. All rotors feature the same chiral geometry.

Contrary to current knowledge, our results show that this chiral fluid displays different flows whose chirality

is not necessarily analogous to the chirality of its constituent particles. We will show that these transitions are

controlled by particle spin and translational velocity correlations and heat dissipation at the boundaries.

Most notably, we will show that particle spin synchronization within the fluid leads to an inversion of the flow chirality, this

inversion resulting from a continuous transition where inverse chiral vortexes appear gradually.

We finally describe a mechanisms through which a set of active particles can control their global rotation state

and hence their transport properties. Our results are relevant for a variety of important biological processes