Dynamics of active particles with space-dependent swim velocity

Caprini, Lorenzo; Marconi, Umberto Marini Bettolo; Wittmann, René; Löwen, Hartmut

doi:10.1039/d1sm01648b

Cited by 32 publications

(41 citation statements)

References 101 publications

(149 reference statements)

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“…Remarkably, even in this crude approximation, we see from the factor (1 + α) 2 that the oscillations of the swim velocity lead to a decrease of the second moment x 2 of ρ(x) compared to the homogeneous case u(x) = v 0 . This prediction is consistent with previous results obtained in the absence of an external potential, where the swimvelocity oscillations produce the decrease of the long-time diffusion coefficient [70] (see also Ref. [87]).…”

Section: A Density Distributionsupporting

confidence: 93%

“…The required expression (15) for p s (x, v) is the exact solution of the potential-free active system with spatial-dependent swim velocity as derived in Ref. [70]: it is a Gaussian probability distribution for the particle velocity v with an effective space-dependent kinetic temperature provided by u 2 (x). The spatial density ρ s (x) from Eq.…”

Section: A Multiscale Methods For the Full-space Distributionmentioning

confidence: 99%

“…To describe an active particle with spatially-dependent swim velocity, we employ the stochastic model introduced in Ref. [70], representing a generalization of the AOUP dynamics. The position of the active particle, x, evolves according to overdamped dynamics supplemented by a stochastic equation for the active driving, the so-called selfpropulsion (or active) force, f a .…”

Section: Model a Active Particles With Spatial-dependent Swim Velocitymentioning

confidence: 99%

“…To ease the theoretical treatment of the model and gain further analytic insight, we switch to the auxiliary dynamics employed earlier in the potential-free case [70]. Instead of describing the system in terms of position x and self-propulsion velocity u(x)η, we take advantage of the relation (holding for D t = 0)…”

Section: Velocity Description Of Aoupmentioning

confidence: 99%

“…The present authors recently modified the AOUP model to include a space-dependent swim velocity in Ref. [70] and obtained exact results for both the density profile and velocity distribution of a potential-free particle.…”

Section: Introductionmentioning

confidence: 99%

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Active particles driven by competing spatially dependent self-propulsion and external force

Caprini¹,

Marconi²,

Wittmann³

et al. 2022

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We investigate how the competing presence of a nonuniform motility landscape and an external confining field affects the properties of active particles. We employ the active Ornstein-Uhlenbeck particle (AOUP) model with a periodic swim velocity profile to derive analytical approximations for the steady-state probability distribution of position and velocity, encompassing both the Unified Colored Noise Approximation and the theory of potential-free active particles with spatially dependent swim velocity recently developed. We test the theory by confining an active particle in a harmonic trap, which gives rise to interesting properties, such as a transition from a unimodal to a bimodal (and, eventually multimodal) spatial density, induced by decreasing the spatial period of the self propulsion. Correspondingly, the velocity distribution shows pronounced deviations from the Gaussian shape, even displaying a bimodal profile in the high-motility regions. Our results can be confirmed by real-space experiments on active colloidal Janus particles in external fields.

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Section: A Density Distributionsupporting

confidence: 93%

Section: A Multiscale Methods For the Full-space Distributionmentioning

confidence: 99%

Section: Model a Active Particles With Spatial-dependent Swim Velocitymentioning

confidence: 99%

Section: Velocity Description Of Aoupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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