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Related papers: Floating flocks: Two-dimensional long-range uniaxi…

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The emergence of long-range spatiotemporal order from intrinsic chaos is a central challenge in far-from-equilibrium physics. In active fluids, such as cytoskeletal networks driving cellular motion, self-generated flows typically produce…

Because active particles break time-reversal symmetry, an active fluid can sustain currents even without an external drive. We show that when a passive body is placed in a fluid of pairwise interacting active particles, it generates…

Statistical Mechanics · Physics 2020-08-26 Omer Granek , Yongjoo Baek , Yariv Kafri , Alexandre P. Solon

We present the hydrodynamic theory of coherent collective motion ("flocking") at a solid-liquid interface, and many of its predictions for experiment. We find that such systems are stable, and have long-range orientational order, over a…

Soft Condensed Matter · Physics 2022-01-05 Niladri Sarkar , Abhik Basu , John Toner

We develop an effective two-dimensional coarse-grained description for the coupled system of a planar fluid membrane anchored to a thin layer of polar ordered active fluid below. The macroscopic orientation of the active fluid layer is…

Soft Condensed Matter · Physics 2013-09-16 Niladri Sarkar , Abhik Basu

Chaotic transitions in inertial fluids typically proceed through a direct energy cascade from large to small scales. In contrast, active systems, composed of self propelled units, inject energy at microscopic scales and therefore exhibit an…

Soft Condensed Matter · Physics 2026-04-14 Partha Sarathi Mondal , Tamas Vicsek , Shradha Mishra

A surface in contact with the isotropic phase of a passive liquid crystal can induce nematic order over distances that range from microscopic to macroscopic when the nematic-isotropic interface undergoes an orientational-wetting transition.…

Soft Condensed Matter · Physics 2024-03-18 Rodrigo C. V. Coelho , José A. Moreira , Duarte M. C. Pedro , Margarida M. Telo da Gama

We formulate the hydrodynamics of active columnar phases, with two-dimensional translational order in the plane perpendicular to the columns and no elastic restoring force for relative sliding of the columns, using the general formalism of…

Soft Condensed Matter · Physics 2023-06-14 S. J. Kole , Gareth P. Alexander , Ananyo Maitra , Sriram Ramaswamy

We study how hydrodynamic interactions affect the collective behaviour of active particles suspended in a fluid at high concentrations, with particular attention to lubrication forces which appear when the particles are very close to one…

Soft Condensed Matter · Physics 2018-05-29 Natsuhiko Yoshinaga , Tanniemola B. Liverpool

Simulations employing the continuum model of Gao et al. [Phy. Rev. Fluids, 2 093302 (2017)] are used to study the transport of an object in a closed two-dimensional container by a dense suspension of contractile active agents. For…

Fluid Dynamics · Physics 2023-11-29 Jonathan B. Freund

Because active particles break time-reversal symmetry, a single non-spherical body placed in an active fluid generates currents. We show that when two or more passive bodies are placed in an active fluid these currents lead to long-range…

Statistical Mechanics · Physics 2018-02-07 Yongjoo Baek , Alexandre P. Solon , Xinpeng Xu , Nikolai Nikola , Yariv Kafri

Living materials at different length scales manifest active nematic features such as orientational order, nematic topological defects, and active nematic turbulence. Using numerical simulations we investigate the impact of fluid inertia on…

Soft Condensed Matter · Physics 2022-08-10 Roozbeh Saghatchi , Mehmet Yildiz , Amin Doostmohammadi

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…

Soft Condensed Matter · Physics 2025-09-03 Niels de Graaf Sousa , Simon Guldager Andersen , Aleksandra Ardaševa , Amin Doostmohammadi

Colloidal particles that are confined to an interface such as the air-water interface are an example of a two-dimensional fluid. Such dispersions have been observed to spontaneously form cluster and stripe morphologies in certain systems…

Soft Condensed Matter · Physics 2008-09-17 A. J. Archer

We investigate the susceptibility of long-range ordered phases of two-dimensional dry aligning active matter to population disorder, taken in the form of a distribution of intrinsic individual chiralities. Using a combination of…

Soft Condensed Matter · Physics 2021-12-15 Bruno Ventejou , Hugues Chaté , Raul Montagne , Xia-qing Shi

We investigate fluids of dipolar hard particles by a certain variant of density-functional theory. The proper treatment of the long range of the dipolar interactions yields a contribution to the free energy which favors ferromagnetic order.…

Condensed Matter · Physics 2009-10-28 B. Groh , S. Dietrich

The study of liquid crystals at equilibrium has led to fundamental insights into the nature of ordered materials, as well as to practical applications such as display technologies. Active nematics are a fundamentally different class of…

Soft Condensed Matter · Physics 2015-08-19 Stephen J. DeCamp , Gabriel S. Redner , Aparna Baskaran , Michael F. Hagan , Zvonimir Dogic

So-called polar liquid crystals possess spontaneous long-range mutual orientation of their electric dipole moments, conferring bulk polarity to fluid phases of matter. The combination of polarity and fluidity leads to complex phase…

Soft Condensed Matter · Physics 2025-08-22 Jordan Hobbs , Calum J. Gibb , Richard J. Mandle

Active fluids exhibit spontaneous flows with complex spatiotemporal structure, which have been observed in bacterial suspensions, sperm cells, cytoskeletal suspensions, self-propelled colloids, and cell tissues. Despite occurring in the…

Soft Condensed Matter · Physics 2022-10-05 Ricard Alert , Jaume Casademunt , Jean-François Joanny

We propose a simple deterministic dynamic equation and reveal the mechanism of large-scale endless evolvement of spatial density inhomogeneity in active nematic. We determine the phase regions analytically. The interplay of density,…

Statistical Mechanics · Physics 2010-11-25 Xia-qing Shi , Yu-qiang Ma

Orientational and positional ordering properties of liquid crystal monolayers are examined by means of Fundamental-Measure Density Functional Theory. Particles forming the monolayer are modeled as hard parallelepipeds of square section of…

Soft Condensed Matter · Physics 2015-06-19 Yuri Martinez-Raton , Szabolcs Varga y Enrique Velasco