Dynamics and escape of active particles in a harmonic trap

Wexler, Dan; Gov, Nir S.; Rasmussen, Kim Ø.; Bel, Golan

doi:10.1103/physrevresearch.2.013003

Cited by 42 publications

(21 citation statements)

References 66 publications

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“…This has important implications for many works studying tracer dynamics, coupling of motors to the matrix, trap escape, etc. in active gels [68][69][70][71][72]: are these results qualitatively changed by the heavy tails in the noise? where r = r/|r|.…”

Section: Discussionmentioning

confidence: 99%

Active gels, heavy tails, and the cytoskeleton

Swartz,

Camley

2021

Preprint

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The eukaryotic cell's cytoskeleton is a prototypical example of an active material: objects embedded within it are driven by molecular motors acting on the cytoskeleton, leading to anomalous diffusive behavior. Experiments tracking the behavior of cell-attached objects have observed anomalous diffusion with a distribution of displacements that is non-Gaussian, with heavy tails. This has been attributed to "cytoquakes" or other spatially extended collective effects. We show, using simulations and analytical theory, that a simple continuum active gel model driven by fluctuating force dipoles naturally creates heavy power-law tails in cytoskeletal displacements. We predict that this power law exponent should depend on the geometry and dimensionality of where force dipoles are distributed through the cell; we find qualitatively different results for force dipoles in a 3D cytoskeleton and a quasi-two-dimensional cortex. We then discuss potential applications of this model both in cells and in synthetic active gels.

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Section: Discussionmentioning

confidence: 99%

Active gels, heavy tails, and the cytoskeleton

Swartz,

Camley

2021

Preprint

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“…is given by Eqs. (A4) and (A5) [42,50]. The internal energy increases with time as the effective temperature increases with the activity.…”

Section: Active Particle Heat Enginementioning

confidence: 99%

Exactly solvable model of a passive Brownian heat engine and its comparison with active engines

Majumdar,

Saha,

Marathe

2021

Preprint

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We perform an extensive analysis of passive as well as active micro-heat engines with different single-particle stochastic models. Using stochastic thermodynamics we calculate thermodynamic work, heat, entropy production and efficiency of passive and active Brownian heat engines analytically as well as numerically and compare them. We run the heat engines with a group of protocols for which, the average thermodynamic quantities are calculated exactly for an arbitrary cycle time.We obtain detailed thermodynamics of non-quasistatic (i.e. powerful) single-particle micro heat engines. The quasistatic (i.e. zero power) limit of the results is obtained by taking large (infinite) cycle time. We also study the distributions of position of the confined particle in both passive and active engines. We compare their characteristics in terms of the parameter that measures the competition between the active persistence in the particle position (due to active noises) and the harmonic confinement. We also calculate excess kurtosis that measures the non-Gaussianity of these distributions. Our analysis shows that efficiency of such thermal machine can be enhanced or reduced depending on the activity present in the model.

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“…24) and ∆U 2 eff (Eq. 25) depend on the active parameters (C 0 , f B , τ A ) and ambient temperature T in a complex way unlike the case where the barrier height is simply shifted by a constant due to activity [49].…”

Section: Variation Of Nonmentioning

confidence: 99%

“…More recently, the notion of effective potential has emerged as an alternative approach to describe the Kramers' escape under self-propulsion rather than effective temperature [49]. In another study, Pierro et.…”

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confidence: 99%

Escape of a passive particle from activity-induced energy landscape: Emergence of slow and fast effective diffusion

Chaki,

Chakrabarti

2020

Preprint

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Spontaneous persistent motions driven by active processes play a central role to maintain the living cells far from equilibrium. In the majority of the research works, the steady state dynamics of an active system has been described in terms of an effective temperature. By contrast, we have examined a prototype model for diffusion in an activity-induced rugged energy landscape to describe the slow dynamics of a tagged particle in a dense active environment. The expression for the mean escape time from the active rugged energy landscape holds only in the limit of low activity and the mean escape time from the rugged energy landscape increases with activity. The precise form of the active correlation will determine whether the mean escape time will depend on the persistence time or not. The active rugged energy landscape approach also allows an estimate of non-equilibrium effective diffusivity characterizing the slow diffusive motion of the tagged particle due to activity. On the other hand, in a dilute environment, high activity augments the diffusion of the tagged particle. The enhanced diffusion can be attributed to an effective temperature, higher than the ambient temperature and is used to calculate the Kramers' mean escape time, which decreases with activity. Our results have direct relevance to recent experiments on tagged particle diffusion in condensed phases. I. INTRODUCTIONSystems composed of active particles represent a class of driven non-equilibrium systems in which the driving forces are direct, isotropic and controlled locally rather than globally [1,2]. They can either be found in biological systems such as bacterial colonies [3], motile cells in tissues [4], cytoskeleton in living cells [5] or are realized artificially such as catalytic Janus particles [6]. While the former are typically self-propelled by the chemical energy

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Dynamics and escape of active particles in a harmonic trap

Cited by 42 publications

References 66 publications

Active gels, heavy tails, and the cytoskeleton

Active gels, heavy tails, and the cytoskeleton

Exactly solvable model of a passive Brownian heat engine and its comparison with active engines

Escape of a passive particle from activity-induced energy landscape: Emergence of slow and fast effective diffusion

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