scholarly journals Active Brownian particles: mapping to equilibrium polymers and exact computation of moments

Soft Matter ◽  
2020 ◽  
Vol 16 (20) ◽  
pp. 4776-4787 ◽  
Author(s):  
Amir Shee ◽  
Abhishek Dhar ◽  
Debasish Chaudhuri
Keyword(s):  
Brownian Particle ◽  
Exact Calculation ◽  
Exact Computation ◽  
Brownian Particles ◽  
Active Brownian Particle ◽  
Equilibrium Polymers

A polymer-mapping of active Brownian particle (ABP)-trajectories, and exact calculation of the moments of dynamical variables provide insights into the mechanical crossovers in polymers with length, and related dynamical crossovers in ABP-motion.

scholarly journals Whirligig beetles as corralled active Brownian particles

2021 ◽  
Vol 18 (177) ◽  
Author(s):  
Harvey L. Devereux ◽  
Colin R. Twomey ◽  
Matthew S. Turner ◽  
Shashi Thutupalli
Keyword(s):  
Phase Separation ◽  
Condensed Phase ◽  
Open Space ◽  
Brownian Particle ◽  
Low Density ◽  
Speed Scaling ◽  
New Model ◽  
Density Dependent ◽  
Brownian Particles ◽  
Active Brownian Particle

We study the collective dynamics of groups of whirligig beetles Dineutus discolor (Coleoptera: Gyrinidae) swimming freely on the surface of water. We extract individual trajectories for each beetle, including positions and orientations, and use this to discover (i) a density-dependent speed scaling like v ∼ ρ − ν with ν ≈ 0.4 over two orders of magnitude in density (ii) an inertial delay for velocity alignment of approximately 13 ms and (iii) coexisting high and low-density phases, consistent with motility-induced phase separation (MIPS). We modify a standard active Brownian particle (ABP) model to a corralled ABP (CABP) model that functions in open space by incorporating a density-dependent reorientation of the beetles, towards the cluster. We use our new model to test our hypothesis that an motility-induced phase separation (MIPS) (or a MIPS like effect) can explain the co-occurrence of high- and low-density phases we see in our data. The fitted model then successfully recovers a MIPS-like condensed phase for N = 200 and the absence of such a phase for smaller group sizes N = 50, 100.

scholarly journals Morphological transitions of active Brownian particle aggregates on porous walls

Soft Matter ◽  
2020 ◽  
Vol 16 (31) ◽  
pp. 7250-7255 ◽  
Author(s):  
Suchismita Das ◽  
Raghunath Chelakkot
Keyword(s):  
Brownian Particle ◽  
Morphological Transition ◽  
Brownian Particles ◽  
Particle Aggregates ◽  
Morphological Transitions ◽  
Porous Walls ◽  
Active Brownian Particle

Cluster of aggregated active Brownian particles (ABPs) undergoes morphological transition on porous walls.

Effects of time delay on transport processes in an active Brownian particle

2013 ◽  
Vol 392 (19) ◽  
pp. 4210-4215 ◽  
Author(s):  
Wei Guo ◽  
Can-Jun Wang ◽  
Lu-Chun Du ◽  
Dong-Cheng Mei
Keyword(s):  
Time Delay ◽  
Brownian Particle ◽  
Transport Processes ◽  
Active Brownian Particle

scholarly journals Motility-Induced Microphase and Macrophase Separation in a Two-Dimensional Active Brownian Particle System

2020 ◽  
Vol 125 (17) ◽  
Author(s):  
Claudio B. Caporusso ◽  
Pasquale Digregorio ◽  
Demian Levis ◽  
Leticia F. Cugliandolo ◽  
Giuseppe Gonnella
Keyword(s):  
Particle System ◽  
Brownian Particle ◽  
Two Dimensional ◽  
Active Brownian Particle ◽  
Macrophase Separation

Do hydrodynamic interactions affect the swim pressure?

Soft Matter ◽  
2018 ◽  
Vol 14 (18) ◽  
pp. 3581-3589 ◽  
Author(s):  
Eric W. Burkholder ◽  
John F. Brady
Keyword(s):  
Brownian Particle ◽  
Hydrodynamic Interactions ◽  
Particle Model ◽  
Active Brownian Particle

We generalize the active Brownian particle model to account for hydrodynamic interactions.

scholarly journals Intermediate scattering function of an anisotropic active Brownian particle

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Christina Kurzthaler ◽  
Sebastian Leitmann ◽  
Thomas Franosch
Keyword(s):  
Brownian Particle ◽  
Rotational Diffusion ◽  
Effective Diffusion ◽  
Mean Square Displacement ◽  
Scattering Function ◽  
Directed Motion ◽  
Stochastic Motion ◽  
Length Scales ◽  
Intermediate Scattering Function ◽  
Active Brownian Particle

Abstract Various challenges are faced when animalcules such as bacteria, protozoa, algae, or sperms move autonomously in aqueous media at low Reynolds number. These active agents are subject to strong stochastic fluctuations, that compete with the directed motion. So far most studies consider the lowest order moments of the displacements only, while more general spatio-temporal information on the stochastic motion is provided in scattering experiments. Here we derive analytically exact expressions for the directly measurable intermediate scattering function for a mesoscopic model of a single, anisotropic active Brownian particle in three dimensions. The mean-square displacement and the non-Gaussian parameter of the stochastic process are obtained as derivatives of the intermediate scattering function. These display different temporal regimes dominated by effective diffusion and directed motion due to the interplay of translational and rotational diffusion which is rationalized within the theory. The most prominent feature of the intermediate scattering function is an oscillatory behavior at intermediate wavenumbers reflecting the persistent swimming motion, whereas at small length scales bare translational and at large length scales an enhanced effective diffusion emerges. We anticipate that our characterization of the motion of active agents will serve as a reference for more realistic models and experimental observations.

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