Chirality transitions in a system of active flat spinners

Abstract

We study in this work the 2D dynamics of an experimental system of disk-shaped rotors, fluidized by turbulent upflow. Contrary to previous knowledge, our experiments show the same particle chiral geometry can produce flows with different chiralities. In particular, we unveil a conspicuous complex chiral flow, which displays multiple persistent vortexes with either sign, located randomly in the system. This peculiar phase mediates a continuous transition, which takes place as the kinetic energy input increases, from a flow with positive chirality (one vortex rotating in the same direction as particles spin) to a flow with negative chirality (one vortex in opposite sense to particle spin). We find that these surprising transitions are determined by the specific state of the statistical correlations between particle spin and translational velocity. We discuss how these correlations are determined in turn by the combined action of a series of mechanisms (for instance, heat dissipation at the boundaries, particle activity, average kinetic energy...), several of which are unveiled here.

arXiv comment15 pages, 6 figures (including supplementary material). To appear in Phys. Rev. Research (2022)

References in corpus (15)

• Odd viscosity in chiral active fluids
• Emergent vortices in populations of colloidal rollers
• Emergent collective phenomena in a mixture of hard shapes through active rotation
• Topological waves in fluids with odd viscosity
• Spatiotemporal order and emergent edge currents in active spinner materials
• Hydrodynamics of Random-Organizing Hyperuniform Fluids
• Purely hydrodynamic ordering of rotating disks at a finite Reynolds number
• Topological localization in out-of-equilibrium dissipative systems
• Dynamical Crystallites of Active Chiral Particles
• Polar state memory in active fluids
• Role of roughness on the hydrodynamic homogeneous base state of inelastic spheres
• Steady base states for Navier-Stokes granular hydrodynamics with boundary heating and shear
• Velocity and Speed Correlations in Hamiltonian Flocks
• Zero-gravity thermal convection in granular gases
• Thermal Schwinger Effect: Defect Production in Compressed Filament Bundles

Cited by in corpus (10)

• Odd Viscosity and Odd Elasticity
• Diffusive regimes in a two-dimensional chiral fluid
• Field-Theory of Active Chiral Hard Disks: A First-Principles Approach to Steric Interactions
• Analytical solution for the hydrodynamic resistance of a disk in a compressible fluid layer with odd viscosity on a rigid substrate
• Inertial Spinner Swarm Experiments: Spin Pumping, Entropy Oscillations and Spin Frustration
• Spin and velocity correlations in a confined two-dimensional fluid of disk-shaped active rotors
• Chirality, confinement and dimensionality govern re-entrant transitions in active matter
• Phase separation in a chiral active fluid of inertial self-spinning disks
• Odd elasticity in disordered chiral active materials
• Kinetic Theory of Chiral Active Disks: Odd Transport and Torque Density