2018/07/21 by N Narinder, Clemens Bechinger, Juan Ruben Gomez-Solano · 1 citation
Engineering · Physics and Astronomy · #Active matter #Angular velocity #Brownian motion #Circular motion #Circular orbit #Classical mechanics #Critical radius #Curvature #Diffusion #Geometry #Mechanics #Micro and Nano Robotics #Microfluidic and Bio-sensing Technologies #Molecular Communication and Nanonetworks #Newtonian fluid #Optics #Physics #Quantum mechanics #RADIUS #Rotation around a fixed axis #Rotational diffusion #cond-mat.soft
paper · pdf · doi:10.1103/physrevlett.121.078003
5 pages, 3 Figures, Phys. Rev. Lett. (accepted 20 July 2018)
arxiv created 2018/07/21 · openalex publication_date 2018/08/17 · arxiv updated 2018/08/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We experimentally study the motion of light-activated colloidal microswimmers in a viscoelastic fluid. We find that, in such a non-Newtonian environment, the active colloids undergo an unexpected transition from enhanced angular diffusion to persistent rotational motion above a critical propulsion speed, despite their spherical shape and stiffness. We observe that, in contrast to chiral asymmetric microswimmers, the resulting circular orbits can spontaneously reverse their sense of rotation and exhibit an angular velocity and a radius of curvature that nonlinearly depend on the propulsion speed. By means of a minimal non-Markovian Langevin model for active Brownian motion, we show that these nonequilibrium effects emerge from the delayed response of the fluid with respect to the self-propulsion of the particle without counterpart in Newtonian fluids.