Small-world rheology: an introduction to probe-based active microrheology

Wilson, Laurence G.; Poon, Wilson

doi:10.1039/c0cp01564d

Cited by 104 publications

(105 citation statements)

References 113 publications

(152 reference statements)

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“…This is an example, similar to others recently pointed out in [7,8], of how the response to an external field may feature anomalous effects in the case of nonlinear dynamics. These topics can find application for instance in probebased microrheology, for the study of the motion of a tracer particle in a disordered system when an external force is applied [9]. We remark that, for our heterogeneous systems, the Einstein relation established in [10,11,12,13,14] proves a proportionality between x 2 (t) and the drift x(t) ǫ , where .…”

Section: Introductionmentioning

confidence: 99%

Rare events and scaling properties in field-induced anomalous dynamics

Burioni¹,

Gradenigo²,

Sarracino³

et al. 2013

J. Stat. Mech.

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Abstract. We show that, in a broad class of continuous time random walks (CTRW), a small external field can turn diffusion from standard into anomalous. We illustrate our findings in a CTRW with trapping, a prototype of subdiffusion in disordered and glassy materials, and in the Lévy walk process, which describes superdiffusion within inhomogeneous media. For both models, in the presence of an external field, rare events induce a singular behavior in the originally Gaussian displacements distribution, giving rise to power-law tails. Remarkably, in the subdiffusive CTRW, the combined effect of highly fluctuating waiting times and of a drift yields a non-Gaussian distribution characterized by long spatial tails and strong anomalous superdiffusion.

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Section: Introductionmentioning

confidence: 99%

Rare events and scaling properties in field-induced anomalous dynamics

Burioni¹,

Gradenigo²,

Sarracino³

et al. 2013

J. Stat. Mech.

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“…The TP dynamics is different from that of the adsorbed particles in two aspects: first, it can not desorb from the lattice and second, it is subject to an external driving force E, which favors its jumps along the direction corresponding to the unit vector e 1 of the lattice. Physically, such a situation is realized in the context of active microrheology where the force on the TP is classically exerted by magnetic tweezers [1].…”

Section: The Modelmentioning

confidence: 99%

“…One measures then the response of the TP and potentially the microstructural deformations of the medium to learn about its microrheological properties. From the theoretical point of view, an unresolved issue, which is disregarded in the available continuous analytical approaches, is to take into account explicitly the discreteness or "granularity" of the medium [1]. This aspect becomes crucial when the probe and the medium particles have comparable sizes, e.g.…”

Section: Introductionmentioning

confidence: 99%

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Fluctuations and correlations of a driven tracer in a hard-core lattice gas

et al. 2013

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We consider a driven tracer particle (TP) in a bath of hard-core particles undergoing continuous exchanges with a reservoir. We develop an analytical framework which allows us to go beyond the standard force-velocity relation used for this minimal model of active microrheology and quantitatively analyze, for any density of the bath particles, the fluctuations of the TP position and their correlations with the occupation number of the bath particles. We obtain an exact Einstein-type relation which links these fluctuations in the absence of a driving force and the bath particles density profiles in the linear driving regime. For the one-dimensional case we also provide an approximate but very accurate explicit expression for the variance of the TP position and show that it can be a non-monotoneous function of the bath particles density: counter-intuitively, an increase of the density may increase the dispersion of the TP position. We show that this non trivial behavior, which could in principle be observed in active microrheology experiments, is induced by subtle cross-correlations quantified by our approach.

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“…In active microrheology, the properties of a medium are probed using the mobility and velocity fluctuations of an externally driven probe particle that is roughly the same size as the particles that comprise the medium [1][2][3][4] . For example, the nonlinear mobility of a probe particle dragged through a colloidal system changes across the glass transition [5][6][7][8] .…”

Section: Introductionmentioning

confidence: 99%

Active microrheology in active matter systems: Mobility, intermittency, and avalanches

Reichhardt

2015

Phys. Rev. E

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We examine the mobility and velocity fluctuations of a driven particle moving through an active matter bath of self-mobile disks for varied density or area coverage and varied activity. We show that the driven particle mobility can exhibit non-monotonic behavior that is correlated with distinct changes in the spatio-temporal structures that arise in the active media. We demonstrate that the probe particle velocity distributions exhibit specific features in the different dynamic regimes, and identify an activity-induced uniform crystallization that occurs for moderate activity levels and that is distinct from the previously observed higher activity cluster phase. The velocity distribution in the cluster phase has telegraph noise characteristics produced when the probe particle moves alternately through high mobility areas that are in the gas state and low mobility areas that are in the dense phase. For higher densities and large activities, the system enters what we characterize as an active jamming regime. Here the probe particle moves in intermittent jumps or avalanches which have power-law distributed sizes that are similar to the avalanche distributions observed for non-active disk systems near the jamming transition.

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Small-world rheology: an introduction to probe-based active microrheology

Cited by 104 publications

References 113 publications

Rare events and scaling properties in field-induced anomalous dynamics

Rare events and scaling properties in field-induced anomalous dynamics

Fluctuations and correlations of a driven tracer in a hard-core lattice gas

Active microrheology in active matter systems: Mobility, intermittency, and avalanches

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