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REVIEW 3 major objections 5 minor 45 references

Self-propulsive active nematics

T0 review · 3 major / 5 minor · reviewed 2026-08-05 · deepseek-v4-flash

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Pith's one-line read Adding a self-advective term to the active nematic equations suppresses the nematic instability above a threshold speed, and at intermediate speeds it maximizes nematic order, turns defect arrangements anti-hyperuniform, and produces long-r

desk verdict The linear stability checks out, but the simulation results all hang on an unregularized flow-locked polarity rule; worth refereeing with major revision. read the letter →

arxiv 2509.02386 v1 pith:HEKT7LXV submitted 2025-09-02 cond-mat.soft

Niels de Graaf Sousa , Simon Guldager Andersen , Aleksandra Ardaševa , Amin Doostmohammadi This is my paper · ORCID
classification cond-mat.soft
keywords activenematicsself-propulsionturbulencenematicinstabilitytopologicaldefectsanti-hyperuniformitylong-rangevorticityorderrotationalsymmetrybreaking
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper argues that a minimal addition to the standard active nematic model—a term that lets each particle advect along a polarity direction—changes the physics of active nematics far beyond a perturbative shift. It shows, first, that self-propulsion above a critical speed V0* stabilizes the homogeneous nematic state, postponing the classical active instability. Second, at intermediate speeds (peaking near V0≈0.06 at activity ζ=0.05) the nematic order and correlation length reach a maximum, and the topological defects arrange into anti-hyperuniform patterns with giant number fluctuations, while vorticity correlations decay with an exponent ν<2, meaning true long-range order. Third, in this same window the system's rotational symmetry is spontaneously broken, and it is restored at larger speeds. If correct, self-propulsion is not just a perturbation but a quantitative control parameter that bridges active turbulence and flocking-like order.

What carries the argument

The central object is the self-advective term V0 p_k ∂_k Q_ij in Equation (1), which breaks nematic symmetry by giving each nematic particle a polarity. The polarity p is not an independent field: it is slaved to the director n̂ and the flow velocity v, with p pointing along the end of the nematic axis that makes the smallest angle with the local flow. This term enters the linear stability analysis through the longitudinal mode, producing the closed-form threshold V0* (Equation 9) that separates the stable and unstable regions. In the nonlinear regime, the same term is responsible for the non-monotonic enhancement of order, the anti-hyperuniform defect configurations, and the broken rotation

What would settle it

A concrete test: run a simulation (or experiment) of self-propelled nematic rods in which the polarity is an independent field with its own relaxation, and measure the correlation length, defect structure factor, and vorticity exponent as a function of swimming speed. If the peak at V0≈0.06 disappears, the predicted optimum and the associated long-range order are artifacts of the flow-locking rule; if the peak persists, the slaving assumption is not the origin of the effect.

Watch

Extended reading notes

Core claim

The central claim is that adding the self-advective term V0 p_k ∂_k Q_ij to the Beris–Edwards equation for the nematic tensor—with the polarity p chosen at each instant as the director end closest to the local flow—makes the homogeneous nematic state linearly stable when V0 exceeds the closed-form threshold V0* = (ΓK + η/ρ)√[(2+λ)/(2ΓKη) (ζ − q²K(2+λ)) − q²], verified by simulations. At lower but non-zero speeds, before the flocking transition, the same term enhances nematic order non-monotonically: at V0≈0.06 the elastic free energy density is minimal and the correlation length maximal. In this ordered window, topological defects exhibit anti-hyperuniform density fluctuations (structure fac

Load-bearing premise

The load-bearing premise is the polarity assignment rule: each particle is assumed to always polarize along the end of its nematic axis that makes the smallest angle with the local flow velocity, so the self-propulsion direction has no independent dynamics.

Editorial extensions

If this is right

  • Above V0*, active nematic suspensions with self-propulsion can remain in a homogeneous, aligned state at activities that would otherwise drive spontaneous turbulence.
  • At intermediate speeds, the defect network becomes anti-hyperuniform, meaning density fluctuations grow faster than the Poisson law—observable as giant number fluctuations in experiment.
  • Vorticity correlations decay with an exponent smaller than the spatial dimension, implying long-range order in the flow and a symmetry-broken, anisotropic state.
  • The non-universal scaling exponents in the kinetic-energy spectrum provide a fingerprint that could be used to detect self-propulsion in experimental systems such as migrating cell monolayers or swarming bacteria.
  • Tuning self-propulsion can therefore be used as a design knob to control order, defect structure, and flow correlations in synthetic active-nematic materials.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the polarity-slaver assumption is relaxed to allow an independent polarity field with its own relaxation and contact alignment, the sharp optimum at V0≈0.06 might broaden or shift; a direct test would be to simulate the nematopolar models cited as [23, 24] with the same parameters.
  • The anti-hyperuniform defect packing at the order maximum suggests a connection to critical-like density fluctuations: measuring the compressibility or the structure factor of the defect gas at very small q could reveal a universality class shared with other active systems at a nonequilibrium critical point.
  • The resumption of rotational symmetry at higher V0 suggests that self-propulsion acts like a reentrant symmetry-breaking field; it may be worth testing whether this reentrance persists when activity ζ is varied along the stability boundary.
  • Because the model uses a single scalar V0, it yields a testable quantitative prediction for real systems: for a given suspension, the correlation length should first grow, peak, and then fall as swimming speed is increased, with the peak location set by the ratio ΓK/η times the V0* expression.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The manuscript proposes a minimal extension of the standard active nematic model by adding a self-advective term V0 p_k ∂_k Q_ij to the Beris–Edwards equation, with polarity p assigned instantaneously as the nematic axis closest to the local flow velocity. A linear stability analysis around a uniformly aligned state yields a closed expression for the critical self-propulsion speed V0* that suppresses the classical active nematic instability. Numerical simulations then report a non-monotonic dependence of nematic order on V0, with a peak near V0≈0.06, defect configurations becoming anti-hyperuniform (α≈−0.9, β≈0.7), long-range vorticity correlations (ν<2), and rotational symmetry breaking that is restored at larger V0. The paper interprets these results as evidence that self-propulsion can bridge active turbulence and ordered regimes.

Significance. If the results are robust, the paper offers a conceptually simple control parameter—self-propulsion speed—for tuning active nematics from turbulent to long-range-ordered states, and it connects to recent experiments on cell monolayers and bacterial colonies. The linear stability calculation is a genuine parameter-free prediction from the stated equations and is tested against simulations, which is a strength. The anti-hyperuniformity and vorticity scaling measurements are also internally cross-checked by independent estimators at V0=0.06. However, the central nonlinear results rest entirely on a sharp, non-dynamical polarity closure, and the reported scaling exponents lack error bars and fitting-range sensitivity analyses. These issues must be addressed before the quantitative claims can be considered established.

major comments (3)
  1. [§II, Eq. (1) and Fig. 1] The model's only polar ingredient is the advective term V0 p·∇Q, with p assigned as the end of n̂ least deviating from the local flow, i.e. p = sign(n̂·v)n̂. This is a discontinuous, non-dynamical closure: it is undefined when n̂·v=0, and no equation of motion, persistence, or noise is introduced for p. Every V0-dependent headline result—the order/correlation-length peak at V0≈0.06, defect anti-hyperuniformity, and vorticity long-range order—is conditioned on this specific rule. The cited experiments [27–29] demonstrate flow alignment in particular settings, but they do not establish that intrinsic polarity is slaved to the local velocity on all scales, especially near topological defects. I request a sensitivity analysis with a regularized closure (e.g., p = n̂ tanh(β n̂·v)) or with a dynamical p (even a simple relaxational equation) to show that the predicted optimum and exponents do n
  2. [§III C, Fig. 4] The exponents α in Fig. 4b are obtained by fitting S(q)∼q^α over |q|≤1/4, but no error bars, number of fitting points, or sensitivity to the fitting range are reported. Fig. 4a shows visible curvature and flattening for V0≥0.08, and the distinction between asymptotic anti-hyperuniformity and finite-range apparent scaling is exactly what such an analysis must demonstrate. The independent window-scaling estimate at V0=0.06 (β≈0.7, α≈−0.8) is welcome, but it is only given for two V0 values. I ask for confidence intervals on α and for explicit q_min sensitivity tests for at least V0=0.04, 0.06, 0.08, and 0.1.
  3. [§III D, Fig. 5] The energy-cascade exponent β and vorticity-decay exponent ν are extracted from insets without error bars and without stating the fitting intervals. The claim ν<2 (long-range vorticity order) depends on the small-q behaviour of the enstrophy spectrum / large-r decay of ⟨ω²(r)⟩; the insets appear to cover only a limited range and the reported values are plotted without uncertainties. Please provide the fit ranges, confidence intervals, and a demonstration that ν is stable under varying the fitting window. This is load-bearing for the 'anomalous long-range order' conclusion.
minor comments (5)
  1. [§III A] Typo: 'longitude' should be 'length' when defining L.
  2. [References] Reference [19] contains a typo: 'Physical Revew E' should be 'Physical Review E'.
  3. [§III B, Fig. 3d] The definition ρe = ⟨E/max(E)⟩ is ambiguous: max(E) over what set—time, space, or both? Please state the normalization explicitly.
  4. [§III D, Fig. 6] The inset defines l∥ and l⊥ but the text does not state how these lengths are extracted. Please define them in the caption or text.
  5. [§III C, Fig. 4c] The number of frames and the stationarity of the defect configuration used for the window counts are not stated. A brief note on temporal averaging and convergence would help.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: all headline results are measured outputs or parameter-free algebraic consequences of the stated model, not reductions to fitted inputs or self-citation chains.

full rationale

The paper's central stability result (Eq. 9) is derived algebraically from the linearized Beris-Edwards/Navier-Stokes equations (Eqs. 1-6) with the self-advective term V0 p_k ∂_k Q; it is not fitted to simulation data. The simulations then independently test this threshold by classifying stable/unstable states, which is a legitimate internal consistency check rather than a circular fit. The anti-hyperuniform exponents (α≈-0.89±0.07, β≈0.7), correlation-length peak at V0≈0.06, vorticity decay exponent ν<2, and rotational symmetry breaking are all measured simulation outputs, not parameters fed back into the model. The polarity assignment p = direction of n̂ closest to v is an explicit modeling assumption (Sec. II, Fig. 1) justified by external experimental citations [27-29]; although [28] shares an author with the present paper, this is an empirical observation and is not the source of the derived results. The absence of a sensitivity analysis for this discontinuous closure is a legitimate robustness concern but does not make the derivation circular. No equation is defined in terms of a target result, and no fitted parameter is renamed as a prediction.

Assumptions & free parameters 1 free parameters · 5 assumptions · 1 invented entities

The model imports the entire standard active nematic apparatus from prior literature and adds exactly one new assumption: the flow-locked polarity assignment rule. No model constant is fitted to data; the only tunable analysis choices are the wave-vector and radius fitting ranges used to extract the exponents α, β, and ν. The auxiliary polarity field is not an independent entity. The dimensional V0 ∝ √ζ argument is illustrative and does not predict the V0 ≈ 0.06 optimum.

free parameters (1)
  • exponent fitting ranges = q <= 1/4 for S(q); R in [L/100, L/10] for number variance
    The exponents α, β, ν are extracted from these ranges; no sensitivity analysis to the ranges is given, so the reported values carry hidden analysis choices.
assumptions (5)
  • domain assumption Standard continuum active nematic hydrodynamics: Beris-Edwards equation (Eq. 1), Landau-de Gennes free energy (Eq. 3), Navier-Stokes with viscous, passive, and active stresses (Eqs. 4-6)
    Inherited from [13, 30, 31]; assumes one-elastic-constant K, constant activity, no density dynamics, and the specific form of the passive stress.
  • ad hoc to paper Polarity is assigned to the end of n̂ least deviating from the local flow (Methods, Fig. 1)
    The defining postulate of the model. All V0-dependent results flow from V0 p·∂Q in Eq. 1. The cited experiments [27-29] motivate flow alignment in specific organisms but do not establish the rule as generic, and no sensitivity to the sign or delay of the alignment is tested.
  • standard math Linear perturbation ansatz (Eq. 7) around a homogeneous x-aligned state with ω = 0 and vx > 0; Qxx decouples
    Standard small-amplitude analysis following [31]; requires the base state to be a solution and the transverse/longitudinal mode decoupling to hold.
  • domain assumption Defect configurations form a translationally invariant, ergodic point process (Appendix B)
    Needed for the periodogram estimate (Eq. B1) to be asymptotically unbiased; plausible at steady state, but not verified for the anti-hyperuniform cases, where the estimator variance is largest.
  • ad hoc to paper Time-scale balance τQ = ΓK/V0² versus τv = η/ζ supporting V0 ∝ √ζ (Section III A)
    Dimensional argument only; it predicts V0 ≈ 0.0035 at the stated parameters, far from the observed optimum V0 ≈ 0.06, so it does not explain the central non-monotonicity.
invented entities (1)
  • auxiliary polarity field p (flow-locked)
    purpose: Carries the self-propulsive advection V0 p·∂Q in Eq. 1 and generates all V0-dependent effects; defined as the n̂ end closest to the local flow
    p is not a dynamical order parameter: it has no equation of motion, no independent defects or fluctuations, and no falsifiable handle outside the model. It is a derived projection of n̂ onto the local flow direction, which is why the 'mixed symmetry' framing in the abstract overstates the model content.

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Cite this review

Pith. "Pith review of Self-propulsive active nematics." pith.science (2026). https://pith.science/paper/HEKT7LXV

@misc{pith2026250902386,
  author       = {Pith},
  title        = {Pith review of: Self-propulsive active nematics},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/HEKT7LXV}},
  note         = {Machine review of arXiv:2509.02386}
}
read the original abstract

Increasing evidence suggests that active matter exhibits instances of mixed symmetry that cannot be fully described by either polar or nematic formalism. Here, we introduce a minimal model that integrates self-propulsion into the active nematic framework. Our linear stability analyses reveal how self-propulsion shifts the onset of instability, fundamentally altering the dynamical landscape. Numerical simulations confirm these predictions, showing that self-propulsion induces anti-hyperuniform fluctuations, anomalous long-range order in vorticity, and non-universal self-similar energy cascades. Notably, these long-range ordered states emerge within the active turbulence regime well before the transition to a flocking state. Additionally, our analyses highlight a non-monotonic dependence of self-organization on self-propulsion, with optimal states characterized by a peak in correlation length. These findings are relevant for understanding of active nematic systems that self-propel, such as migrating cell layers or swarming bacteria, and offer new avenues for designing synthetic systems with tailored collective behaviours, bridging the gap between active nematics and self-propulsive systems.

Figures

Figures reproduced from arXiv: 2509.02386 by the authors.

Figure 1
Figure 1. FIG. 1 [PITH_FULL_IMAGE:figures/full_fig_p006_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p009_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p011_3.png] view at source ↗
Figures from the paper (3 more)
Figure 4
Figure 4. Figure 4: FIG. 4 [PITH_FULL_IMAGE:figures/full_fig_p013_4.png]
Figure 5
Figure 5. Figure 5: FIG. 5 [PITH_FULL_IMAGE:figures/full_fig_p016_5.png]
Figure 6
Figure 6. Figure 6: FIG. 6 [PITH_FULL_IMAGE:figures/full_fig_p018_6.png]

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Reference graph

Works this paper leans on

45 extracted references · 22 canonical work pages

  1. [1]

    2017 Active matter at the interface between materials science and cell biology.Nature Reviews Materials2, 1–14

    Needleman D, Dogic Z. 2017 Active matter at the interface between materials science and cell biology.Nature Reviews Materials2, 1–14. (10.1038/natrevmats.2017.48)

    doi:10.1038/natrevmats.2017.48 2017

  2. [2]

    giant number fluctuations

    As a result, one can find that the instability is suppressed above certain values of V ∗ 0 : V ∗ 0 = ΓK + η ρ s (2 + λ) 2ΓKη [ζ − q2K(2 + λ)] − q2. (9) This expression divides the phase space into stable and unstable regions (black line in Fig. 2) and shows close agreement with the results obtained from numerical simulations. This result proves thatV0 can...

    work page

  3. [3]

    2014 Living liquid crystals.Proceed- ings of the National Academy of Sciences111, 1265–1270

    Zhou S, Sokolov A, Lavrentovich OD, Aranson IS. 2014 Living liquid crystals.Proceed- ings of the National Academy of Sciences111, 1265–1270. (10.1073/pnas.1321926111)

    work page doi:10.1073/pnas.1321926111 2014

  4. [4]

    2022 Bacterial active matter.Reports on Progress in Physics85, 076601

    Aranson IS. 2022 Bacterial active matter.Reports on Progress in Physics85, 076601. (10.1088/1361-6633/ac723d)

    work page doi:10.1088/1361-6633/ac723d 2022

  5. [5]

    2020 Dense active matter model of motion patterns in confluent cell monolayers.Nature Communications 11, 1405

    Henkes S, Kostanjevec K, Collinson JM, Sknepnek R, Bertin E. 2020 Dense active matter model of motion patterns in confluent cell monolayers.Nature Communications 11, 1405. (10.1038/s41467-020-15164-5)

    doi:10.1038/s41467-020-15164-5 2020

  6. [6]

    2018 Turbulent Dynamics of Epithelial Cell Cultures.Physical Review Letters120

    Blanch-Mercader C, Yashunsky V, Garcia S, Duclos G, Giomi L, Silberzan P. 2018 Turbulent Dynamics of Epithelial Cell Cultures.Physical Review Letters120. (10.1103/physrevlett.120.208101)

    doi:10.1103/physrevlett.120.208101 2018

  7. [7]

    2016 Emergent behavior in active colloids.Journal of Physics: Con- densed Matter28, 253001

    Zöttl A, Stark H. 2016 Emergent behavior in active colloids.Journal of Physics: Con- densed Matter28, 253001. (10.1088/0953-8984/28/25/253001)

    doi:10.1088/0953-8984/28/25/253001 2016

  8. [8]

    2020 The 2020 motile active matter roadmap

    Gompper G, Winkler RG, Speck T, Solon A, Nardini C, Peruani F, Löwen H, Golesta- nian R, Kaupp UB, Alvarez L et al.. 2020 The 2020 motile active matter roadmap. Journal of Physics: Condensed Matter32, 193001. (10.1088/1361-648X/ab6348)

    doi:10.1088/1361-648x/ab6348 2020

Show all 45 references
  1. [9]

    2022 Physics of liquid crystals in cell biology.Trends in Cell Biology32, 140–150

    Doostmohammadi A, Ladoux B. 2022 Physics of liquid crystals in cell biology.Trends in Cell Biology32, 140–150. (10.1016/j.tcb.2021.09.012)

    2022 doi

  2. [10]

    2018 Biological tissues as active nematic liquid crystals

    Saw TB, Xi W, Ladoux B, Lim CT. 2018 Biological tissues as active nematic liquid crystals. Advanced Materials30, 1802579. (10.1002/adma.201802579) 22

    2018 doi

  3. [11]

    2014 Defect dy- namics in active nematics.Philosophical Transactions of the Royal Society A: Mathe- matical, Physical and Engineering Sciences372, 20130365

    Giomi L, Bowick MJ, Mishra P, Sknepnek R, Cristina Marchetti M. 2014 Defect dy- namics in active nematics.Philosophical Transactions of the Royal Society A: Mathe- matical, Physical and Engineering Sciences372, 20130365. (10.1098/rsta.2013.0365)

    2014

  4. [12]

    2019 Emergence of active nematics in chaining bacterial biofilms

    Yaman YI, Demir E, Vetter R, Kocabas A. 2019 Emergence of active nematics in chaining bacterial biofilms. Nature Communications 10, 2285. (10.1038/s41467-019- 10311-z)

    2019 doi

  5. [13]

    2018 Active nematics

    Doostmohammadi A, Ignes-Mullol J, Yeomans J, Sagués F. 2018 Active nematics. Nature Communications9. (10.1038/s41467-018-05666-8)

    2018 doi

  6. [14]

    2022 Active Turbulence.Annual Review of Con- densed Matter Physics13, 143–170

    Alert R, Casademunt J, Joanny JF. 2022 Active Turbulence.Annual Review of Con- densed Matter Physics13, 143–170. (10.1146/annurev-conmatphys-082321-035957)

    2022 doi

  7. [15]

    2021 Bac- teria solve the problem of crowding by moving slowly.Nature Physics 17, 205–210

    Meacock OJ, Doostmohammadi A, Foster KR, Yeomans JM, Durham WM. 2021 Bac- teria solve the problem of crowding by moving slowly.Nature Physics 17, 205–210. (10.1038/s41567-020-01070-6)

    2021 doi

  8. [16]

    2024 Topological de- fects lead to energy transfer in active nematics

    Pearce DJ, Martínez-Prat B, Ignés-Mullol J, Sagués F. 2024 Topological de- fects lead to energy transfer in active nematics. arXiv preprint arXiv:2411.18214. (10.48550/arXiv.2411.18214)

    2024 doi

  9. [17]

    2018 Mesoscale physical principles of collective cell organization

    Trepat X, Sahai E. 2018 Mesoscale physical principles of collective cell organization. Nature Physics14, 671–682. (10.1038/s41567-018-0194-9)

    2018 doi

  10. [18]

    2021 Topological defects pro- mote layer formation in Myxococcus xanthus colonies.Nature Physics 17, 211–215

    Copenhagen K, Alert R, Wingreen NS, Shaevitz JW. 2021 Topological defects pro- mote layer formation in Myxococcus xanthus colonies.Nature Physics 17, 211–215. (10.1038/s41567-020-01056-4)

    2021 doi

  11. [19]

    2015 Turbulence of swarm- ing sperm.Physical Revew E92, 032722

    Creppy A, Praud O, Druart X, Kohnke PL, Plouraboué F. 2015 Turbulence of swarm- ing sperm.Physical Revew E92, 032722. (10.1103/PhysRevE.92.032722)

    2015 doi

  12. [20]

    2017 Topological defects control collective dy- namics in neural progenitor cell cultures.Nature 545, 327–331

    Kawaguchi K, Kageyama R, Sano M. 2017 Topological defects control collective dy- namics in neural progenitor cell cultures.Nature 545, 327–331. (10.1038/nature22321) 23

    2017 doi

  13. [21]

    2012 Self-regulation in self-propelled nematic fluids.The European Physical Journal E35, 1–8

    Baskaran A, Marchetti MC. 2012 Self-regulation in self-propelled nematic fluids.The European Physical Journal E35, 1–8. (10.1140/epje/i2012-12095-8)

    2012 doi

  14. [22]

    2008 Hydrodynamics of self-propelled hard rods.Physical Review E—Statistical, Nonlinear, and Soft Matter Physics77, 011920

    Baskaran A, Marchetti MC. 2008 Hydrodynamics of self-propelled hard rods.Physical Review E—Statistical, Nonlinear, and Soft Matter Physics77, 011920. (10.1103/Phys- RevE.77.011920)

    2008 doi

  15. [23]

    2025 Phase diagram, confining strings, and a new universality class in nematopolar matter

    Vafa F, Doostmohammadi A. 2025 Phase diagram, confining strings, and a new universality class in nematopolar matter. arXiv preprint arXiv:2501.04769. (10.48550/arXiv.2501.04769)

    2025 doi arXiv

  16. [24]

    2020 Self-Propelled Rods: Insights and Perspectives for Active Matter.Annual Review of Condensed Matter Physics11, 441–466

    Bär M, Großmann R, Heidenreich S, Peruani F. 2020 Self-Propelled Rods: Insights and Perspectives for Active Matter.Annual Review of Condensed Matter Physics11, 441–466. (10.1146/annurev-conmatphys-031119-050611)

    2020 doi

  17. [25]

    2012 Polar patterns in active fluids.Soft Matter8, 129–139

    Giomi L, Marchetti MC. 2012 Polar patterns in active fluids.Soft Matter8, 129–139. (10.1039/c1sm06077e)

    2012 doi

  18. [26]

    2022 Unifying polar and nematic active matter: emergence and co-existence of half-integer and full-integer topological de- fects

    Amiri A, Mueller R, Doostmohammadi A. 2022 Unifying polar and nematic active matter: emergence and co-existence of half-integer and full-integer topological de- fects. Journal of Physics A: Mathematical and Theoretical55, 094002. (10.1088/1751- 8121/ac4abe)

    2022 doi

  19. [27]

    This behaviour is also shared for bacterium, such asMyxococcus xanthus, where each individual particle aligns with the flow direction [29]

    and epithelial monolayers, which have been observed to align the direction of their lamellipodia and consequently their intrinsic polarity with the total force acting on the cells [28]. This behaviour is also shared for bacterium, such asMyxococcus xanthus, where each individu...

  20. [28]

    2013 Hydrodynamics of soft active matter.Reviews of Modern Physics85, 1143–1189

    Marchetti MC, Joanny JF, Ramaswamy S, Liverpool TB, Prost J, Rao M, Simha RA. 2013 Hydrodynamics of soft active matter.Reviews of Modern Physics85, 1143–1189. Publisher: American Physical Society (10.1103/RevModPhys.85.1143)

    2013 doi

  21. [29]

    2003 Shear flow-induced motility of Dictyostelium discoideum cells on solid substrate.Journal of Cell Science 116, 4331–4338

    Décavé E, Garrivier D, Bréchet Y, Fourcade B, Bruckert F. 2003 Shear flow-induced motility of Dictyostelium discoideum cells on solid substrate.Journal of Cell Science 116, 4331–4338. (10.1242/jcs.00726) 24

    2003 doi

  22. [30]

    2019 Sustained oscillations of epithelial cell sheets

    Peyret G, Mueller R, d’Alessandro J, Begnaud S, Marcq P, Mège RM, Yeomans JM, Doostmohammadi A, Ladoux B. 2019 Sustained oscillations of epithelial cell sheets. Biophysical Journal117, 464–478. (10.1016/j.bpj.2019.06.013)

    2019 doi

  23. [31]

    2023 Local polar order controls mechanical stress and triggers layer formation in developing Myxococcus xanthuscolonies

    Han E, Fei C, Alert R, Copenhagen K, Koch MD, Wingreen NS, Shaevitz JW. 2023 Local polar order controls mechanical stress and triggers layer formation in developing Myxococcus xanthuscolonies. ArXiv. (10.48550/arXiv.2308.00368)

    2023 doi arXiv

  24. [32]

    (10.1103/PhysRevE.76.031921)

    MarenduzzoD,OrlandiniE,CatesME,YeomansJM.2007Steady-statehydrodynamic instabilities of active liquid crystals: Hybrid lattice Boltzmann simulations.Physical Review E76, 031921. (10.1103/PhysRevE.76.031921)

    doi

  25. [33]

    2012 Banding, excitability and chaos in active nematic suspensions

    Giomi L, Mahadevan L, Chakraborty B, Hagan MF. 2012 Banding, excitability and chaos in active nematic suspensions. Nonlinearity 25, 2245–2269. (10.1088/0951- 7715/25/8/2245)

    2012 doi

  26. [34]

    2020 Activity Induced Nematic Order in Isotropic Liquid Crystals

    Santhosh S, Nejad MR, Doostmohammadi A, Yeomans JM, Thampi SP. 2020 Activity Induced Nematic Order in Isotropic Liquid Crystals. Journal of Statistical Physics 180, 699–709. (10.1007/s10955-020-02497-0)

    2020 doi

  27. [35]

    2021 Inertia Drives a Flocking Phase Transition in Viscous Active Fluids.Physical Review X 11, 031063

    Chatterjee R, Rana N, Simha RA, Perlekar P, Ramaswamy S. 2021 Inertia Drives a Flocking Phase Transition in Viscous Active Fluids.Physical Review X 11, 031063. (10.1103/PhysRevX.11.031063)

    2021 doi

  28. [36]

    2015 Intrinsic free energy in active nematics

    Thampi SP, Doostmohammadi A, Golestanian R, Yeomans JM. 2015 Intrinsic free energy in active nematics. Europhysics Letters 112, 28004. (10.1209/0295- 5075/112/28004)

    2015 doi

  29. [37]

    2018 Hyperuniform states of matter

    Torquato S. 2018 Hyperuniform states of matter. Physics Reports 745, 1–95. (10.1016/j.physrep.2018.03.001)

    2018 doi

  30. [38]

    2021 Local Number Fluctuations in Hyperuniform and Nonhyperuniform Systems: Higher-Order Moments and Distribution Functions

    Torquato S, Kim J, Klatt MA. 2021 Local Number Fluctuations in Hyperuniform and Nonhyperuniform Systems: Higher-Order Moments and Distribution Functions. Physical Review X11. (10.1103/physrevx.11.021028) 25

    2021 doi

  31. [39]

    1995 Long-Range Order in a Two-Dimensional DynamicalXY Model: How Birds Fly Together.Physical Review Letters75, 4326–4329

    Toner J, Tu Y. 1995 Long-Range Order in a Two-Dimensional DynamicalXY Model: How Birds Fly Together.Physical Review Letters75, 4326–4329. Publisher: American Physical Society (10.1103/PhysRevLett.75.4326)

    1995 doi

  32. [40]

    2015 Geometry and topology of turbulence in active nematics.Physical Re- view X 5, 031003

    Giomi L. 2015 Geometry and topology of turbulence in active nematics.Physical Re- view X 5, 031003. (10.1103/PhysRevX.5.031003)

    2015 doi

  33. [41]

    2015 New class of turbulence in active fluids.Proceedings of the National Academy of Sciences112, 15048–15053

    Bratanov V, Jenko F, Frey E. 2015 New class of turbulence in active fluids.Proceedings of the National Academy of Sciences112, 15048–15053. (10.1073/pnas.1509304112)

    2015 doi

  34. [42]

    2017 Topological defects in epithelia govern cell death and extrusion.Nature 544, 212–216

    Saw TB, Doostmohammadi A, Nier V, Kocgozlu L, Thampi S, Toyama Y, Marcq P, Lim CT, Yeomans JM, Ladoux B. 2017 Topological defects in epithelia govern cell death and extrusion.Nature 544, 212–216. (10.1038/nature21718)

    2017 doi

  35. [43]

    2021 Cell migration guided by long-lived spatial memory.Nature Commu- nications 12, 4118

    d’Alessandro J, Barbier-Chebbah A, Cellerin V, Benichou O, Mège R, Voituriez R, Ladoux B. 2021 Cell migration guided by long-lived spatial memory.Nature Commu- nications 12, 4118. (10.1038/s41467-021-24249-8)

    2021 doi

  36. [44]

    2024 Individual bacterial cells can use spatial sensing of chemical gradients to direct chemotaxis on surfaces.Nature Microbiology9, 2308–2322

    Wheeler JHR, Foster KR, Durham WM. 2024 Individual bacterial cells can use spatial sensing of chemical gradients to direct chemotaxis on surfaces.Nature Microbiology9, 2308–2322. (10.1038/s41564-024-01729-3)

    2024 doi

  37. [45]

    2023 On estimating the structure factor of a point process, with applications to hyperuniformity.Statistics and Comput- ing 33

    Hawat D, Gautier G, Bardenet R, Lachièze-Rey R. 2023 On estimating the structure factor of a point process, with applications to hyperuniformity.Statistics and Comput- ing 33. (10.1007/s11222-023-10219-1) 26

    2023 doi

Pith tools

Reviewed August 5, 2026 · model on record in the stance chip above.