Collisions Enhance Self-Diffusion in Odd-Diffusive Systems

Kalz, Erik; Vuijk, Hidde Derk; Abdoli, Iman; Sommer, Jens‐Uwe; Löwen, Hartmut; Sharma, Abhinav

doi:10.1103/physrevlett.129.090601

Cited by 19 publications

(22 citation statements)

References 51 publications

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“…In a confined channel, thermal fluctuations of the wall could possibly enhance the diffusion coefficient of particles, as we have seen in the limiting case of an incompressible fluid (Marbach et al 2018). Another recent work finds that diffusion of odd-diffusing interacting particles is enhanced with increasing densities (Kalz et al 2022). While the physical set-up in Kalz et al (2022) is very different from ours, the mathematical similarities that lead to diffusion enhancement are striking (for example, comparing their Eq.…”

Section: Collisions Enhance Diffusionmentioning

confidence: 49%

“…Particles therefore spend time exploring the bulges before escaping the constrictions, and their diffusion coefficient is consequently decreased, D eff ≤ D 0 . This effect is well captured by the Fick-Jacobs approximation, where transport is reduced due to constrictions acting as effective entropy barriers (Jacobs 1935;Zwanzig 1992;Reguera & Rubí 2001;Kalinay & Percus 2006;Burada et al 2007;Mangeat, Guérin & Dean 2017;Marbach et al 2018;Rubi 2019). At intermediate Péclet numbers Pe 1, τ wall τ diff and the moving boundaries enhance particle motion: particles collide with the moving corrugated walls, which increases their diffusion coefficient overall, D eff ≥ D 0 .…”

Section: Simulation Resultsmentioning

confidence: 99%

“…Another recent work finds that diffusion of odd-diffusing interacting particles is enhanced with increasing densities (Kalz et al. 2022). While the physical set-up in Kalz et al.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Interactions enhance dispersion in fluctuating channels via emergent flows

Wang,

Dean,

Marbach

et al. 2023

J. Fluid Mech.

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Understanding particle motion in narrow channels can guide progress in numerous applications, from filtration to vascular transport. Thermal or active fluctuations of fluid-filled channel walls can slow down or increase the dispersion of tracer particles via entropic trapping in the wall bulges or hydrodynamic flows induced by wall fluctuations, respectively. Previous studies concentrated primarily on the case of a single Brownian tracer. Here, we address what happens when there is a large ensemble of interacting Brownian tracers – a common situation in applications. Introducing repulsive interactions between tracer particles, while ignoring the presence of a background fluid, leads to an effective flow field. This flow field enhances tracer dispersion, a phenomenon reminiscent of that seen for single tracers in incompressible background fluid. We characterise the dispersion by the long-time diffusion coefficient of tracers numerically and analytically with a mean-field density functional analysis. We find a surprising effect where an increased particle density enhances the diffusion coefficient, challenging the notion that crowding effects tend to reduce diffusion. Here, inter-particle interactions push particles closer to the fluctuating channel walls. Interactions between the fluctuating wall and the now-nearby particles then drive particle mixing. Our mechanism is sufficiently general that we expect it to apply to various systems. In addition, our perturbation theory quantifies dispersion in generic advection–diffusion systems.

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Section: Collisions Enhance Diffusionmentioning

confidence: 49%

Section: Simulation Resultsmentioning

confidence: 99%

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Interactions enhance dispersion in fluctuating channels via emergent flows

Wang,

Dean,

Marbach

et al. 2023

J. Fluid Mech.

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“…In continuum models, this has been shown to both enhance diffusivity and create directional particle fluxes. 39 Each passive particle leads to a non-vanishing steady-state mass current in its proximity. Fig.…”

Section: Odd Diffusivity Drives Assemblymentioning

confidence: 99%

“…The oscillatory autocorrelation functions that we observe are consistent with recent theoretical work for odd diffusive dynamics. 40 With the boundary fluxes and the diffusion tensor determined, we then solve for the steady-state density profile using finite differences. We describe the numerical details in Section B.1.…”

Section: Odd Diffusivity Drives Assemblymentioning

confidence: 99%

Microscopic origin of tunable assembly forces in chiral active environments

Batton,

Rotskoff

2024

Soft Matter

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Chiral active particles are sensitive reporters to environmental geometry

Chan,

Wu,

Qiao

et al. 2024

Nat Commun

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Chiral active particles (CAPs) are self-propelling particles that break time-reversal symmetry by orbiting or spinning, leading to intriguing behaviors. Here, we examined the dynamics of CAPs moving in 2D lattices of disk obstacles through active Brownian dynamics simulations and granular experiments with grass seeds. We find that the effective diffusivity of the CAPs is sensitive to the structure of the obstacle lattice, a feature absent in achiral active particles. We further studied the transport of CAPs in obstacle arrays under an external field and found a reentrant directional locking effect, which can be used to sort CAPs with different activities. Finally, we demonstrated that parallelogram lattices of obstacles without mirror symmetry can separate clockwise and counter-clockwise CAPs. The mechanisms of the above three novel phenomena are qualitatively explained. As such, our work provides a basis for designing chirality-based tools for single-cell diagnosis and separation, and active particle-based environmental sensors.

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Collisions Enhance Self-Diffusion in Odd-Diffusive Systems

Cited by 19 publications

References 51 publications

Interactions enhance dispersion in fluctuating channels via emergent flows

Interactions enhance dispersion in fluctuating channels via emergent flows

Microscopic origin of tunable assembly forces in chiral active environments

Chiral active particles are sensitive reporters to environmental geometry

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