Active motion of passive asymmetric dumbbells in a non-equilibrium bath
Name
JCP20-AR-03789.pdf
Description
Accepted version
Size
1.23 MB
Format
Adobe PDF
Checksum (MD5)
0a77649e4f4d4805195e45c6c2573e7b
Author(s)
Belan, Sergey
Kardar, Mehran
Date Issued
2021
Journal
The Journal of Chemical Physics
Publisher
AIP Publishing
Citation
Belan, Sergey and Kardar, Mehran. 2021. "Active motion of passive asymmetric dumbbells in a non-equilibrium bath." The Journal of Chemical Physics, 154 (2).
Version
Author's final manuscript
Abstract
© 2021 Author(s). Persistent motion of passive asymmetric bodies in non-equilibrium media has been experimentally observed in a variety of settings. However, fundamental constraints on the efficiency of such motion are not fully explored. Understanding such limits, and ways to circumvent them, is important for efficient utilization of energy stored in agitated surroundings for purposes of taxis and transport. Here, we examine such issues in the context of erratic movements of a passive asymmetric dumbbell driven by non-equilibrium noise. For uncorrelated (white) noise, we find a (non-Boltzmann) joint probability distribution for the velocity and orientation, which indicates that the dumbbell preferentially moves along its symmetry axis. The dumbbell thus behaves as an Ornstein-Uhlenbeck walker, a prototype of active matter. Exploring the efficiency of this active motion, we show that in the over-damped limit, the persistence length l of the dumbbell is bound from above by half its mean size, while the propulsion speed v∥ is proportional to its inverse size. The persistence length can be increased by exploiting inertial effects beyond the over-damped regime, but this improvement always comes at the price of smaller propulsion speeds. This limitation is explained by noting that the diffusivity of a dumbbell, related to the product v∥ l, is always less than that of its components, thus severely constraining the usefulness of passive dumbbells as active particles.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Attribution-NonCommercial-ShareAlike 4.0 International
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1063/5.0030623
