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Title: Communication: Memory effects and active Brownian diffusion

A self-propelled artificial microswimmer is often modeled as a ballistic Brownian particle moving with constant speed aligned along one of its axis, but changing direction due to random collisions with the environment. Similarly to thermal noise, its angular randomization is described as a memoryless stochastic process. Here, we speculate that finite-time correlations in the orientational dynamics can affect the swimmer’s diffusivity. To this purpose, we propose and solve two alternative models. In the first one, we simply assume that the environmental fluctuations governing the swimmer’s propulsion are exponentially correlated in time, whereas in the second one, we account for possible damped fluctuations of the propulsion velocity around the swimmer’s axis. The corresponding swimmer’s diffusion constants are predicted to get, respectively, enhanced or suppressed upon increasing the model memory time. Possible consequences of this effect on the interpretation of the experimental data are discussed.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [4]
  1. Department of Chemistry, Presidency University, Kolkata 700073 (India)
  2. Center for Phononics and Thermal Energy Science, Tongji University, Shanghai 200092 (China)
  3. Dipartimento di Fisica, Università di Camerino, I-62032 Camerino (Italy)
  4. (Italy)
Publication Date:
OSTI Identifier:
22493281
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 21; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COLLISIONS; CORRELATIONS; DIFFUSION; FLUCTUATIONS; NOISE; PARTICLES; PROPULSION; RANDOMNESS; STOCHASTIC PROCESSES; VELOCITY