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Main Authors: Villalobos, Cristian, Cordero, María Luisa, Clément, Eric, Soto, Rodrigo
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2403.11933
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author Villalobos, Cristian
Cordero, María Luisa
Clément, Eric
Soto, Rodrigo
author_facet Villalobos, Cristian
Cordero, María Luisa
Clément, Eric
Soto, Rodrigo
contents The properties of an active fluid, for example, a bacterial bath or a collection of microtubules and molecular motors, can be accessed through the dynamics of passive particle probes. Here, in the perspective of analyzing experimental situations of confinement in droplets, we consider the kinematics of a negatively buoyant probe particle in an active fluid, both confined within a spherical domain. The active bath generates a fluctuating flow that pushes the particle with a velocity that is modeled as a colored stochastic noise, characterized by two parameters, the intensity and memory time of the active flow. When the particle departs a little from the bottom of the spherical domain, the configuration is well approximated by a particle in a two-dimensional harmonic trap subjected to the colored noise, in which case an analytical solution exists, which is the base for quantitative analysis. We numerically simulate the dynamics of the particle and use the planar, two-dimensional mean square displacement to recover the activity parameters of the bath. This approach yields satisfactory results as long as the particle remains relatively confined, that is, as long as the intensity of the colored noise remains low.
format Preprint
id arxiv_https___arxiv_org_abs_2403_11933
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Recovering the activity parameters of an active fluid confined in a sphere
Villalobos, Cristian
Cordero, María Luisa
Clément, Eric
Soto, Rodrigo
Soft Condensed Matter
Mesoscale and Nanoscale Physics
Biological Physics
The properties of an active fluid, for example, a bacterial bath or a collection of microtubules and molecular motors, can be accessed through the dynamics of passive particle probes. Here, in the perspective of analyzing experimental situations of confinement in droplets, we consider the kinematics of a negatively buoyant probe particle in an active fluid, both confined within a spherical domain. The active bath generates a fluctuating flow that pushes the particle with a velocity that is modeled as a colored stochastic noise, characterized by two parameters, the intensity and memory time of the active flow. When the particle departs a little from the bottom of the spherical domain, the configuration is well approximated by a particle in a two-dimensional harmonic trap subjected to the colored noise, in which case an analytical solution exists, which is the base for quantitative analysis. We numerically simulate the dynamics of the particle and use the planar, two-dimensional mean square displacement to recover the activity parameters of the bath. This approach yields satisfactory results as long as the particle remains relatively confined, that is, as long as the intensity of the colored noise remains low.
title Recovering the activity parameters of an active fluid confined in a sphere
topic Soft Condensed Matter
Mesoscale and Nanoscale Physics
Biological Physics
url https://arxiv.org/abs/2403.11933