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Related papers: Active Ising Models of Flocking: A Field-Theoretic…

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It is shown how to explicitly coarse-grain the microscopic dynamics of the Vicsek model for self-propelled agents. The macroscopic transport equations are derived by means of an Enskog-type kinetic theory. Expressions for all transport…

Biological Physics · Physics 2015-02-24 Thomas Ihle

Kinetic and hydrodynamic theories are widely employed for describing the collective behaviour of active matter systems. At the fluctuating level, these have been obtained from explicit coarse-graining procedures in the limit where each…

Statistical Mechanics · Physics 2022-12-14 Ouassim Feliachi , Marc Besse , Cesare Nardini , Julien Barré

Starting from microscopic $N$ particle systems, we study the derivation of Doi type models for suspensions of non-spherical particles in Stokes flows. While Doi models accurately describe the effective evolution of the spatial particle…

Analysis of PDEs · Mathematics 2025-10-22 David Gérard-Varet , Richard M. Höfer

The accumulation of self-propelled particles on repulsive barriers is a widely observed feature in active matter. Despite being implicated in a broad range of biological processes, from biofilm formation to cytoskeletal movement, wetting of…

Statistical Mechanics · Physics 2025-12-12 Noah Grodzinski , Michael E. Cates , Robert L. Jack

We use the Fokker-Planck equation and its moment equations to study the collective behavior of interacting particles in unsteady one-dimensional flows. Particles interact according to a long-range attractive and a short-range repulsive…

Fluid Dynamics · Physics 2014-08-05 Maryam Abedi , Mir Abbas Jalali

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

Self-propelled particles that are subject to noise are a well-established generic model system for active matter. A homogeneous alignment field can be used to orient the direction of the self-propulsion velocity and to model systems like…

Statistical Mechanics · Physics 2024-03-06 Sameh Othman , Jiarul Midya , Thorsten Auth , Gerhard Gompper

We study a model of flocking in order to describe the transitions during the collective motion of organisms in three dimensions (e.g., birds). In this model the particles representing the organisms are self-propelled, i.e., they move with…

Biological Physics · Physics 2015-06-26 A. Czirok , M. Vicsek , T. Vicsek

By studying a system of Brownian particles, interacting only through a local social-like force (velocity alignment), we show that self-propulsion is not a necessary feature for the flocking transition to take place as long as underdamped…

Statistical Mechanics · Physics 2015-07-31 Victor Dossetti , Francisco J. Sevilla

There are rich emergent phase behaviors in non-equilibrium active systems. Flocking and clustering are two representative dynamic phases. The relationship between these two phases is still unclear. In the paper, we numerically investigate…

Soft Condensed Matter · Physics 2023-08-09 Lu Chen , Bokai Zhang , Z. C. Tu

The behavior of many magnetic and dielectric solids, and the more contemporary magnetic super-lattices, is governed by dipolar interactions. They are anisotropic and long-ranged, having varied consequences ranging from ground states with…

Statistical Mechanics · Physics 2021-08-25 Shikha Kumari , Sanjay Puri , Varsha Banerjee

Self-diffusiophoretic particles exploit local concentration gradients of a solute species in order to self-propel at the micron scale. While an isolated chemically- and geometrically-isotropic particle cannot swim, we show that it can…

Soft Condensed Matter · Physics 2018-06-12 Akhil Varma , Thomas D. Montenegro-Johnson , Sebastien Michelin

Natural flocks (aligned) and swarms (non-aligned) both exhibit features of near-criticality, challenging their treatment as two ends of the same phase transition. We present a model for the aggregation of active individuals, in which their…

Adaptation and Self-Organizing Systems · Physics 2025-11-26 Joao Lizárraga , Marcus de Aguiar

Active suspensions, which consist of suspended self-propelling particles such as swimming microorganisms, often exhibit non-trivial transport properties. Continuum models are frequently employed to elucidate phenomena in active suspensions,…

Soft Condensed Matter · Physics 2024-10-14 Lloyd Fung , Hakan O. Caldag , Martin A. Bees

We develop the hydrodynamic theory of dry, polar ordered, active matter (``flocking") with autochemotaxis; i.e., self-propelled entities moving in the same direction, each emitting a substance which attracts the others (e.g., ants). We find…

Soft Condensed Matter · Physics 2024-01-22 Maxx Miller , John Toner

Two hallmarks of non-equilibrium systems, from active colloids to animal herds, are agents motility and nonreciprocal interactions. Their interplay creates feedback loops leading to complex spatiotemporal dynamics crucial to understand and…

Statistical Mechanics · Physics 2025-09-17 David Martin , Daniel Seara , Yael Avni , Michel Fruchart , Vincenzo Vitelli

Recently, we proposed a self-propelled particle model with competing alignment interactions: nearby particles tend to align their velocities whereas they anti-align their direction of motion with particles which are further away [R.…

Soft Condensed Matter · Physics 2016-05-02 Robert Großmann , Pawel Romanczuk , Markus Bär , Lutz Schimansky-Geier

We investigate the behavior of self-propelled particles in infinite space dimensions by comparing two powerful approaches in many-body dynamics: the Fokker-Planck equation and dynamical mean-field theory. The dynamics of the particles at…

A continuum model for a population of self-propelled particles interacting through nematic alignment is derived from an individual-based model. The methodology consists of introducing a hydrodynamic scaling of the corresponding mean-field…

Analysis of PDEs · Mathematics 2015-09-11 Pierre Degond , Angelika Manhart , Hui Yu

Understanding the organization of collective motion in biological systems is an ongoing challenge. In this Paper we consider a minimal model of self-propelled particles with variable speed. Inspired by experimental data from schooling fish,…

Biological Physics · Physics 2015-06-04 Shradha Mishra , Kolbjørn Tunstrøm , Iain D. Couzin , Cristián Huepe