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Related papers: Small Obstacle in a Large Polar Flock

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We introduce a family of lattice-gas models of flocking, whose thermodynamically consistent dynamics admits a proper equilibrium limit at vanishing self-propulsion. These models are amenable to an exact coarse-graining which allows us to…

Statistical Mechanics · Physics 2024-09-27 Tal Agranov , Robert L. Jack , Michael E. Cates , Étienne Fodor

We consider an ultra-small system of polarized bosons on an optical lattice with a ring topology interacting via long range dipole-dipole interactions. Dipoles polarized perpendicular to the plane of the ring reveal sharp transitions…

Quantum Gases · Physics 2013-05-29 Michal Maik , Pierfrancesco Buonsante , Alessandro Vezzani , Jakub Zakrzewski

Living groups move in complex environments and are constantly subject to external stimuli, predatory attacks and disturbances. An efficient response to such perturbations is vital to maintain the group's coherence and cohesion.…

Statistical Mechanics · Physics 2023-04-12 Emanuele Loffredo , Davide Venturelli , Irene Giardina

We study, numerically, the collective dynamics of self-rotating nonaligning particles by considering a monolayer of spheres driven by constant clockwise or counterclockwise torques. We show that hydrodynamic interactions alter the emergence…

Soft Condensed Matter · Physics 2016-03-24 Kyongmin Yeo , Enkeleida Lushi , Petia M. Vlahovska

Unlike the substantial coherent bulk motion in which our local patch of the Cosmos is participating, the amplitude of the random motions around this large scale flow seems to be surprisingly low. Attempts to invoke global explanations to…

Astrophysics · Physics 2007-05-23 Rien van de Weygaert , Yehuda Hoffman

Systematic deflection of microparticles off of initial streamlines is a fundamental task in microfluidics, aiming at applications including sorting, accumulation, or capture of the transported particles. In a large class of setups,…

Fluid Dynamics · Physics 2026-04-01 Partha Kumar Das , Xuchen Liu , Sascha Hilgenfeldt

We study a stochastic model of collective motion in which individuals update their orientation through pairwise aligning or anti-aligning copying interactions. We analyze both annealed dynamics, where interaction types are chosen…

Statistical Mechanics · Physics 2026-04-23 Chunming Zheng

The large density of matter in the interaction region of the proton-nucleus or deuteron-nucleus collisions enables the collective expansion of the fireball. Predictions of the hydrodynamic model for the asymmetric transverse flow are…

Nuclear Theory · Physics 2015-06-22 Piotr Bozek , Wojciech Broniowski

We study clustering and percolation phenomena in the Vicsek model, taken here in its capacity of prototypical model for dry aligning active matter. Our results show that the order-disorder transition is not related in any way to a…

Soft Condensed Matter · Physics 2019-09-04 Nikos Kyriakopoulos , Hugues Chaté , Francesco Ginelli

We determine the asymptotic behaviour of (bilateral) obstacle problems for fractional energies in rather general aperiodic settings via Gamma-convergence arguments. As further developments we consider obstacles with random sizes and shapes…

Analysis of PDEs · Mathematics 2009-09-29 Matteo Focardi

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

The macroscopic behavior of dense suspensions of neutrally-buoyant spheres in turbulent plane channel flow is examined. We show that particles larger than the smallest turbulence scales cause the suspension to deviate from the continuum…

Fluid Dynamics · Physics 2016-09-28 Pedro Costa , Francesco Picano , Luca Brandt , Wim-Paul Breugem

We investigate models in which blocking can interrupt a particulate flow process at any time. Filtration, and flow in micro/nano-channels and traffic flow are examples of such processes. We first consider concurrent flow models where…

Statistical Mechanics · Physics 2015-06-15 Andrea Gabrielli , Julian Talbot , Pascal Viot

Self-propelled particles with anti-aligning interactions generally do not form a polar order. However, in this Letter, we show that when multiple types of such particles coexist and interact through aligning interactions between different…

Soft Condensed Matter · Physics 2025-12-08 Takahiro Oki , Tetsuhiro S. Hatakeyama , Seiya Nishikawa , Shuji Ishihara , Toshinori Namba

Microorganisms often encounter strong confinement and complex hydrodynamic flows while navigating their habitats. Combining finite-element methods and stochastic simulations, we study the interplay of active transport and heterogeneous…

Soft Condensed Matter · Physics 2025-11-05 Pallabi Das , Mirko Residori , Axel Voigt , Suvendu Mandal , Christina Kurzthaler

Fluids with internal microstructure like dense suspensions, biological and polymer added fluids, are commonly found in the turbulent regime in many applications. Their flow is extremely difficult to be studied as microstructure complexity…

Fluid Dynamics · Physics 2020-11-11 G. Sofiadis , I. E. Sarris

Field control provides a practical route to programmable active matter, yet how weak fields modify non-equilibrium coexistence and interfaces remains unclear. To address this, we study a minimal flocking model of active Potts particles…

Soft Condensed Matter · Physics 2026-03-30 Mintu Karmakar , Matthieu Mangeat , Swarnajit Chatterjee , Heiko Rieger , Raja Paul

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

Non-reciprocal systems exhibit diverse dynamical phases whose character depends on the type and degree of non-reciprocity. In this study, we theoretically investigate dynamical structures in a mixture of non-reciprocally aligning polar…

Soft Condensed Matter · Physics 2024-12-20 Kim L. Kreienkamp , Sabine H. L. Klapp

Previous particle-based computer simulations have revealed a significantly more pronounced tendency of spontaneous global polar ordering in puller (contractile) microswimmer suspensions than in pusher (extensile) suspensions. We here…

Soft Condensed Matter · Physics 2018-10-23 Christian Hoell , Hartmut Löwen , Andreas M. Menzel