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We use a continuum, two-fluid approach to study a mixture of two active nematic fluids. Even in the absence of thermodynamically-driven ordering, for mixtures of different activities we observe turbulent microphase separation, where domains…

Soft Condensed Matter · Physics 2025-02-03 Saraswat Bhattacharyya , Julia M. Yeomans

We numerically model a two-dimensional active nematic confined by a periodic array of fixed obstacles. Even in the passive nematic, the appearance of topological defects is unavoidable due to planar anchoring by the obstacle surfaces. We…

Soft Condensed Matter · Physics 2024-01-25 Cody D. Schimming , C. J. O. Reichhardt , C. Reichhardt

We numerically study two-dimensional active nematics with periodic activity patterning. For stripes of activity, we observe a transition from two-dimensional to one-dimensional active turbulence as the maximum active force and distance…

Soft Condensed Matter · Physics 2025-03-11 Cody D. Schimming , C. J. O. Reichhardt , C. Reichhardt

Here we study theoretically the dynamics of a 2D and a 3D isotropic droplet in a nematic liquid crystal under a shear flow. We find a large repertoire of possible nonequilibrium steady states as a function of the shear rate and of the…

Soft Condensed Matter · Physics 2016-09-06 A. Tiribocchi , M. Da Re , D. Marenduzzo , E. Orlandini

Using computer simulations we investigate the microscopic structure of the singular director field within a nematic droplet. As a theoretical model for nematic liquid crystals we take hard spherocylinders. To induce an overall topological…

Soft Condensed Matter · Physics 2009-10-31 J. Dzubiella , M. Schmidt , H. Loewen

Topological defects are fundamental to the collective dynamics of non-equilibrium systems and in active matter, mediating spontaneous flows, dynamic self-organization, and emergent pattern formation. Here, we reveal critical states in…

Active-elastic instabilities are common phenomena in the natural world which have the aspect of sudden mechanical morphings. Frequently, the driving force of the instability mechanisms has a chemo-mechanical nature which makes these kind of…

Soft Condensed Matter · Physics 2020-11-13 Michele Curatolo , Gaetano Napoli , Paola Nardinocchi , Stefano Turzi

A nematic liquid crystal in contact with a grating surface possessing an alternating stripe pattern of locally homeotropic and planar anchoring is studied within the Frank--Oseen model. The combination of both chemical and geometrical…

Soft Condensed Matter · Physics 2009-11-11 L. Harnau , S. Kondrat , A. Poniewierski

We characterise the particlelike kinematics of charge-carrying topological defects in nematic media via a geometric field theory. This differs from the theory of electromagnetism, with which it is often compared, due to the absence of…

Soft Condensed Matter · Physics 2026-05-22 Joseph Pollard , Richard G. Morris

Real-life bacteria often swim in complex fluids, but our understanding of the interactions between bacteria and complex surroundings is still evolving. In this work, rod-like \textit{Bacillus subtilis} swims in a quasi-2D environment with…

We set up and study the hydrodynamic theory for inversion-symmetric active fluid and tethered membranes. For some choices of the activity parameter, such membranes are stable and described by linear hydrodynamic equations, which are exact…

Statistical Mechanics · Physics 2025-06-17 Sudip Mukherjee , Abhik Basu

Within the framework of continuum theory, we draw a parallel between ferromagnetic materials and nematic liquid crystals confined on curved surfaces, which are both characterized by local interaction and anchoring potentials. We show that…

Soft Condensed Matter · Physics 2022-02-22 Gaetano Napoli , Oleksandr V. Pylypovskyi , Denis D. Sheka , Luigi Vergori

We investigate energetically favorable configurations of point disclinations in nematic films having a bump geometry. Gradual expansion in the bump width {\Delta} gives rise to a sudden shift in the stable position of the disclinations from…

Soft Condensed Matter · Physics 2015-05-20 Isaku Hasegawa , Hiroyuki Shima

Using numerical simulations, we characterized the behavior of an elastic membrane immersed in an active fluid. Our findings reveal a nontrivial folding and re-expansion of the membrane that is controlled by the interplay of its resistance…

Soft Condensed Matter · Physics 2015-07-24 S. A. Mallory , C. Valeriani , A. Cacciuto

We study the organization of topological defects in a system of nematogens confined to the two-dimensional sphere (S^2). We first perform Monte Carlo simulations of a fluid system of hard rods (spherocylinders) living in the tangent plane…

Soft Condensed Matter · Physics 2009-11-13 Homin Shin , Mark J. Bowick , Xiangjun Xing

We investigate the switching dynamics of multistable nematic liquid crystal devices. In particular we identify a remarkably simple 2-dimensional (2D) device which exploits hybrid alignment at the surfaces to yield a bistable response. We…

Soft Condensed Matter · Physics 2011-02-08 A. Tiribocchi , G. Gonnella , D. Marenduzzo , E. Orlandini

The nonlinear elastic properties of nematic liquid crystals have acquired new interest with the recent experimental observation of bulk modulated nematic phases which are composed by achiral molecules. We extend the Oseen-Zocher-Frank's…

Soft Condensed Matter · Physics 2018-11-09 I. Lelidis , G. Barbero

We present a generic framework for modelling three-dimensional deformable shells of active matter that captures the orientational dynamics of the active particles and hydrodynamic interactions on the shell and with the surrounding…

Soft Condensed Matter · Physics 2019-11-20 Luuk Metselaar , Julia M. Yeomans , Amin Doostmohammadi

Many vesicles have a spherical resting shape and exposure to fluid flows induces an exchange between sub-optical area and visible (systematic) deformation, while the total area is conserved. The dynamics which controls the exchange between…

Soft Condensed Matter · Physics 2020-06-19 Afsoun Rahnama Falavarjani , David Salac

Biological membranes are host to proteins and molecules which may form domain-like structures resulting in spatially-varying material properties. Vesicles with such heterogeneous membranes can exhibit intricate shapes at equilibrium and…

Soft Condensed Matter · Physics 2023-06-22 Prerna Gera , David Salac , Saverio E. Spagnolie