Turbulence-to-order transitions in activity-patterned active nematics

Physical review. E, Journal Year: 2025, Volume and Issue: 111(3)

Published: March 7, 2025

We numerically study two-dimensional active nematics with periodic activity patterning. For stripes of activity, we observe a transition from to one-dimensional turbulence as the maximum force and distance between increases, followed by stable vortices ordered antiferromagnetically along ferromagnetically transverse stripes. By comparing triangular lattice circles, find that transitions emerge interplays length scale density, independent patterning geometry. The vortex ordering, however, is highly sensitive geometry, which show columns where ordering lost. Our results provide mechanism for inducing nonequilibrium phase in using inhomogeneity, can be further exploited create patterned phases.

Language: Английский

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Periodic orbits, pair nucleation, and unbinding of active nematic defects on cones

Physical review. E, Journal Year: 2024, Volume and Issue: 109(6)

Published: June 7, 2024

Geometric confinement and topological constraints present promising means of controlling active materials. By combining analytical arguments derived from the Born-Oppenheimer approximation with numerical simulations, we investigate simultaneous impact together curvature singularity by characterizing dynamics an nematic on a cone. Here, that textures can follow defect positions rapidly timescales interest. Upon imposing strong anchoring boundary conditions at base cone, find rich phase diagram multidefect dynamics, including exotic periodic orbits one or two +1/2 flank defects, depending activity nonquantized geometric charge cone apex. transitions between these ordered dynamical states, detailed understanding (i) unbinding, (ii) absorption, (iii) pair nucleation Numerical simulations confirm theoretical predictions not only nature circular but also unbinding

Language: Английский

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Feedback Control of Active Matter

Annual Review of Condensed Matter Physics, Journal Year: 2025, Volume and Issue: 16(1), P. 319 - 341

Published: March 10, 2025

Feedback control is essential to the performance of dynamical systems, helping drive nonequilibrium systems from one state another. In this review, we discuss feedback applied living and synthetic active matter—systems that are constantly out equilibrium. We review experimental theoretical work in controlling trajectory distribution matter, single particles collective populations. Modern advances microscopy numerical computation have enabled data-rich studies aided by data-driven approaches model, forecast, complex chaotic behaviors matter. describe basic mathematical structure Brownian particles, with a focus on observability time delay embedding particle motion using density data alone. Finally, comment future outlook multibody interparticle hydrodynamic interactions.

Language: Английский

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Synthetic Active Liquid Crystals Powered by Acoustic Waves

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 26, 2025

Active nematic materials combine orientational order with activity at the microscopic level. Current experimental realizations of active nematics include vibrating elongated particles, cell layers, suspensions bacteria, and a mixture bio-filaments molecular motors. The majority are biological origin. realization fully synthetic liquid crystal comprised lyotropic chromonic energized by ultrasonic waves, is reported. This free from degradation variability, exhibits phenomenology associated nematics, enables precise rapid control over significantly extended range. It demonstrated that energy acoustic field converted into extensile stresses disrupting long-range giving rise to an undulation instability proliferation topological defects. emergence unconventional free-standing persistent vortices in director high levels revealed. results provide foundation for design externally crystals stable material properties tunable defect dynamics crucial reconfigurable microfluidic systems.

Language: Английский

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Achieving designed texture and flows in bulk active nematics using optimal control theory

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(13)

Published: April 1, 2025

Being intrinsically nonequilibrium, active materials can potentially perform functions that would be thermodynamically forbidden in passive materials. However, systems have diverse local attractors correspond to distinct dynamical states, many of which exhibit chaotic turbulent-like dynamics and thus cannot work or useful functions. Designing such a system choose specific state is formidable challenge. Motivated by recent advances enabling optogenetic control experimental materials, we describe an optimal theory framework identifies spatiotemporal sequence light-generated activity drives nematic toward prescribed steady state. Active nematics are unstable spontaneous defect proliferation streaming the absence control. We demonstrate compute fields redirect into variety alternative programs This includes dynamically reconfiguring between selecting stabilizing emergent behaviors do not attractors, hence uncontrolled system. Our results provide roadmap leverage optical methods rationally design structure, dynamics, function wide

Language: Английский

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Defect self-propulsion in active nematic films with spatially varying activity

Royal Society Open Science, Journal Year: 2023, Volume and Issue: 10(2)

Published: Feb. 1, 2023

We study the dynamics of topological defects in active nematic films with spatially varying activity and consider two set-ups: (i) a constant gradient (ii) sharp jump activity. A extensile (contractile) endows comet-like +1/2 defect finite vorticity that drives to align its nose direction decreasing (increasing) gradient. does not, however, affect known self-propulsion has no effect on −1/2 remains non-motile particle. acts like wall traps defects, affecting translational rotational motion both charges. The slows down as it approaches interface net tends reorient polarization so becomes perpendicular interface. acquires towards interface, while vorticity-induced torque preferred orientation. This effective attraction negative is consistent observation an accumulation charge at active/passive interfaces physical boundaries.

Language: Английский

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Chirality, anisotropic viscosity and elastic anisotropy in three-dimensional active nematic turbulence

Communications Physics, Journal Year: 2024, Volume and Issue: 7(1)

Published: July 7, 2024

Abstract Various active materials exhibit strong spatio-temporal variability of their orientational order known as turbulence, characterised by irregular and chaotic motion topological defects, including colloidal suspensions, biofilaments, bacterial colonies.In particular in three dimensions, it has not yet been explored how turbulence responds to changes material parameters chirality.Here, we present a numerical study three-dimensional (3D) nematic examining the influence main constants: (i) flow-alignment viscosity, (ii) magnitude anisotropy elastic deformation modes (elastic constants), (iii) chirality. Specifically, this parameter space covers contractile or extensile, flow-aligning flow tumbling, chiral achiral elastically anisotropic fluids. The results are presented using time- space-averaged fields defect density mean square velocity. also discuss velocity possible effective nematics, distinguishing two states—active blue phase turbulence. This research contributes understanding providing sweep help guide future experimental design use materials.

Language: Английский

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Learning protocols for the fast and efficient control of active matter

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Oct. 23, 2024

Exact analytic calculation shows that optimal control protocols for passive molecular systems often involve rapid variations and discontinuities. However, similar baselines are not generally available active-matter systems, because it is more difficult to treat active exactly. Here we use machine learning derive efficient find they characterized by sharp features those seen in systems. We show possible learn effect fast state-to-state transformations simulation models of particles encoding the protocol form a neural network. evolutionary methods identify take from one steady state another, as quickly or with little energy expended possible. Our results identified flexible neural-network ansatz, which allows optimization multiple parameters emergence features, than derived recently constrained analytical methods. scheme straightforward experiment, suggesting way designing manipulation matter laboratory.

Language: Английский

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Spatiotemporal control of structure and dynamics in a polar active fluid

Soft Matter, Journal Year: 2024, Volume and Issue: 20(35), P. 7059 - 7071

Published: Jan. 1, 2024

We apply optimal control theory to a model of polar active fluid (the Toner-Tu model), with the objective driving system into particular emergent dynamical behaviors or programming switching between states on demand. use effective self-propulsion speed as parameter (

Language: Английский

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Analytical model for the motion and interaction of two-dimensional active nematic defects

Soft Matter, Journal Year: 2024, Volume and Issue: 21(1), P. 122 - 136

Published: Nov. 26, 2024

We develop an analytical model for the motion and interaction of defects in active nematics. analyze detail interactions two show that gives predictions trajectories multiple confinement.

Language: Английский

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