Force-free and autonomous active Brownian ratchets (a)

Autonomous active Brownian ratchets rectify active Brownian particle motion solely by means of a spatially modulated but stationary activity, without external forces. We argue that such ratcheting requires at least a two-dimensional geometry. The underlying principle is similar to the ratcheting ind...

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Bibliographic Details
Published in:Europhysics letters 2023-05, Vol.142 (3), p.31001
Main Authors: Rein, Constantin, Kolář, Martin, Kroy, Klaus, Holubec, Viktor
Format: Article
Language:English
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Summary:Autonomous active Brownian ratchets rectify active Brownian particle motion solely by means of a spatially modulated but stationary activity, without external forces. We argue that such ratcheting requires at least a two-dimensional geometry. The underlying principle is similar to the ratcheting induced by steric obstacles in microswimmer baths: suitably polarized swimmers get channeled, while the others get trapped in low-activity regions until they lose direction. The maximum current is generally reached in the limit of large propulsion speeds, in which the rectification efficiency vanishes. Maximum efficiency is attained at intermediate activities and numerically found to be on the order of a few percent, for ratchets with simple wedge-shaped low-activity regions.
ISSN:0295-5075
1286-4854
DOI:10.1209/0295-5075/accca5