Irreversibility in scalar active turbulence: the role of topological defects
Abstract
Abstract In many active systems, swimmers collectively stir the surrounding fluid to stabilize some self-sustained vortices. The resulting nonequilibrium state is often referred to as active turbulence. Although active turbulence clearly operates far from equilibrium, it can be challenging to pinpoint which emergent features primarily control the deviation from an equilibrium reversible dynamics. Here, we reveal that dynamical irreversibility essentially stems from singularities in the active stress. Specifically, considering the coupled dynamics of the swimmer density and the stream function, we demonstrate that the symmetries of vortical flows around defects determine the overall irreversibility. Our detailed analysis leads to identifying specific configurations of defect pairs as the dominant contribution to irreversibility.
Fields of Study & Subjects
Micro and Nano Robotics
Biomimetic flight and propulsion mechanisms
Fluid Dynamics and Thin Films
Publication details
- Journal / source
- New Journal of Physics
- Publisher
- IOP Publishing
- Volume
- 28
- Issue
- 3
- Pages
- 034601–034601
- Publication date
- 11 February 2026
- Language
- EN