Non-equilibrium properties of an active nanoparticle in a harmonic potential
Artikel i vetenskaplig tidskrift, 2021

Active particles break out of thermodynamic equilibrium thanks to their directed motion, which leads to complex and interesting behaviors in the presence of confining potentials. When dealing with active nanoparticles, however, the overwhelming presence of rotational diffusion hinders directed motion, leading to an increase of their effective temperature, but otherwise masking the effects of self-propulsion. Here, we demonstrate an experimental system where an active nanoparticle immersed in a critical solution and held in an optical harmonic potential features far-from-equilibrium behavior beyond an increase of its effective temperature. When increasing the laser power, we observe a cross-over from a Boltzmann distribution to a non-equilibrium state, where the particle performs fast orbital rotations about the beam axis. These findings are rationalized by solving the Fokker-Planck equation for the particle’s position and orientation in terms of a moment expansion. The proposed self-propulsion mechanism results from the particle’s non-sphericity and the lower critical point of the solution.

Författare

Falko Schmidt

Göteborgs universitet

Hana Jungová

Chalmers, Fysik, Nano- och biofysik

Mikael Käll

Chalmers, Fysik, Nano- och biofysik

Alois Würger

Université de Bordeaux

Giovanni Volpe

Göteborgs universitet

Nature Communications

2041-1723 (ISSN)

Vol. 12 1 1902

Ämneskategorier

Fysikalisk kemi

Atom- och molekylfysik och optik

Annan fysik

DOI

10.1038/s41467-021-22187-z

PubMed

33772007

Mer information

Senast uppdaterat

2021-04-22