Anomalous Magnetotransport in Disordered Structures: Classical Edge-State Percolation

Schirmacher, Walter; Fuchs, Benedikt; Höfling, Felix; Franosch, Thomas

doi:10.1103/physrevlett.115.240602

Cited by 28 publications

(40 citation statements)

References 63 publications

(109 reference statements)

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“…gravitational) force [21]. It also serves as a reference to characterize the non-equilibrium behavior of these chiral particles exposed to spatially heterogeneous media [52,53]. Similarly, it might be a useful input to establish sorting mechanisms of microswimmers according to their (chiral) transport properties [34,54].…”

Section: Discussionmentioning

confidence: 99%

Intermediate scattering function of an anisotropic Brownian circle swimmer

Kurzthaler

Franosch

2017

Soft Matter

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Microswimmers exhibit noisy circular motion due to asymmetric propulsion mechanisms, their chiral body shape, or by hydrodynamic couplings in the vicinity of surfaces. Here, we employ the Brownian circle swimmer model and characterize theoretically the dynamics in terms of the directly measurable intermediate scattering function. We derive the associated Fokker-Planck equation for the conditional probabilities and provide an exact solution in terms of generalizations of the Mathieu functions. Different spatiotemporal regimes are identified reflecting the bare translational diffusion at large wavenumbers, the persistent circular motion at intermediate wavenumbers and an enhanced effective diffusion at small wavenumbers. In particular, the circular motion of the particle manifests itself in characteristic oscillations at a plateau of the intermediate scattering function for wavenumbers probing the radius.

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Section: Discussionmentioning

confidence: 99%

Intermediate scattering function of an anisotropic Brownian circle swimmer

Kurzthaler

Franosch

2017

Soft Matter

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“…A heterogeneous environment can be realized in different ways, both in experiments and theory, e.g., by regular or irregular patterns of obstacles [20][21][22][23][24][25][26][27][28][29][30][31][32], mazes [33], arrays of funnels [16,[34][35][36][37][38], pinning substrates [39], or patterned light fields, which control the velocity of the microswimmer [40,41]. For a review see [4,42].…”

Section: Introductionmentioning

confidence: 99%

Active Brownian particles moving in a random Lorentz gas

2017

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Abstract. Biological microswimmers often inhabit a porous or crowded environment such as soil. In order to understand how such a complex environment influences their spreading, we numerically study noninteracting active Brownian particles (ABPs) in a two-dimensional random Lorentz gas. Close to the percolation transition in the Lorentz gas, they perform the same subdiffusive motion as ballistic and diffusive particles. However, due to their persistent motion they reach their long-time dynamics faster than passive particles and also show superdiffusive motion at intermediate times. While above the critical obstacle density η c the ABPs are trapped, their long-time diffusion below ηc is strongly influenced by the propulsion speed v 0. With increasing v0, ABPs are stuck at the obstacles for longer times. Thus, for large propulsion speed, the long-time diffusion constant decreases more strongly in a denser obstacle environment than for passive particles. This agrees with the behavior of an effective swimming velocity and persistence time, which we extract from the velocity autocorrelation function.

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“…This has been rationalized [54,55] by an underlying percolation transition of disks made of obstacles and 'halos' thus associating an effective radius σ + R to each obstacle. Last, at densities n * > n * c a localized state emerges since the void space between the obstacles ceases to percolate, such that the microswimmers are trapped in separated pockets of void space, resulting in no long-range transport.…”

Section: Model and Methodsmentioning

confidence: 99%

Random motion of a circle microswimmer in a random environment

Chepizhko

Franosch

2020

New J. Phys.

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We simulate the dynamics of a single circle microswimmer exploring a disordered array of fixed obstacles. The interplay of two different types of randomness, quenched disorder and stochastic noise, is investigated to unravel their impact on the transport properties. We compute lines of isodiffusivity as a function of the rotational diffusion coefficient and the obstacle density. We find that increasing noise or disorder tends to amplify diffusion, yet for large randomness the competition leads to a strong suppression of transport. We rationalize both the suppression and amplification of transport by comparing the relevant time scales of the free motion to the mean period between collisions with obstacles.

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Anomalous Magnetotransport in Disordered Structures: Classical Edge-State Percolation

Cited by 28 publications

References 63 publications

Intermediate scattering function of an anisotropic Brownian circle swimmer

Intermediate scattering function of an anisotropic Brownian circle swimmer

Active Brownian particles moving in a random Lorentz gas

Random motion of a circle microswimmer in a random environment

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