Explanipedia

Robust Edge Flows in Swarming Bacterial Colonies Open

He Li, Hugues Chaté, Masaki Sano, Xia-qing Shi, Hepeng Zhang · 2024

Understanding if and how the chirality of biomolecules is transferred across scales into larger components and active processes remains elusive. For instance, flagellated bacteria swim in helical trajectories but chirality seems absent fro…

Condensation and Synchronization in Aligning Chiral Active Matter Open

Yujia Wang, Bruno Ventéjou, Hugues Chaté, Xia-qing Shi · 2024

We show that spontaneous density segregation in dense systems of aligning circle swimmers is a condensation phenomenon at odds with the phase separation scenarios usually observed in two-dimensional active matter. The condensates, which ta…

Effect of Persistent Noise on the XY Model and Two-Dimensional Crystals Open

Xia-qing Shi, Hugues Chaté · 2024

Two-dimensional (2D) crystals made of active particles were shown recently to be able to experience extremely large spontaneous deformations without melting. The root of this phenomenon was argued to lie in the time-persistence of the orie…

Extreme Spontaneous Deformations of Active Crystals Open

Xia-qing Shi, Cheng Fu, Hugues Chaté · 2023

We demonstrate that two-dimensional crystals made of active particles can experience extremely large spontaneous deformations without melting. Using particles mostly interacting via pairwise repulsive forces, we show that such active cryst…

Small Obstacle in a Large Polar Flock Open

Joan Codina, Benoît Mahault, Hugues Chaté, Jure Dobnikar, Ignacio Pagonabarraga , et al. · 2022

We show that arbitrarily large polar flocks are susceptible to the presence of a single small obstacle. In a wide region of parameter space, the obstacle triggers counterpropagating dense bands leading to reversals of the flow. In very lar…

Susceptibility of Orientationally Ordered Active Matter to Chirality Disorder Open

Bruno Ventéjou, Hugues Chaté, Raúl Montagne, Xia-qing Shi · 2021

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 particle-l…

Activity waves and freestanding vortices in populations of subcritical Quincke rollers Open

Zeng Tao Liu, Yan Shi, Yongfeng Zhao, Hugues Chaté, Xia-qing Shi , et al. · 2021

Significance Active matter is made of units that move or displace others by using energy stored internally or gathered from their environment. In most systems and models considered so far, these self-propelled units are constantly moving. …

Breakdown of Ergodicity and Self-Averaging in Polar Flocks with Quenched Disorder Open

Yu Duan, Benoît Mahault, Yu‐qiang Ma, Xia-qing Shi, Hugues Chaté · 2021

We show that spatial quenched disorder affects polar active matter in ways more complex and far reaching than heretofore believed. Using simulations of the 2D Vicsek model subjected to random couplings or a disordered scattering field, we …

Self-Organized Critical Coexistence Phase in Repulsive Active Particles Open

Xia-qing Shi, Giordano Fausti, Hugues Chaté, Cesare Nardini, Alexandre Solon · 2020

We revisit motility-induced phase separation in two models of active particles interacting by pairwise repulsion and uncover new qualitative features: the resulting dense phase contains gas bubbles distributed algebraically up to a typical…

Breakdown of Ergodicity and Self-Averaging in Polar Flocks with Quenched Disorder Open

Yu Duan, Benoît Mahault, Xia-qing Shi, Hugues Chaté · 2020

We show that spatial quenched disorder affects polar active matter in ways more complex and far-reaching than believed heretofore. Using simulations of the 2D Vicsek model subjected to random couplings or a disordered scattering field, we …

Collective behaviors of self-propelled rods under semi-flexible elastic confinement Open

Ying Zhong, Xia-qing Shi · 2020

In biological active systems there commonly exist active rod-like particles under elastic confinement. Here in this work, we study the collective behavior of self-propelled rods confined in an elastic semi-flexible ring. By changing the de…

Dynamical subclasses of dry active nematics Open

Libing Cai, Hugues Chaté, Yu‐qiang Ma, Xia-qing Shi · 2019

We show that the dominant mode of alignment plays an important role in dry active nematics, leading to two dynamical subclasses defined by the nature of the instability of the nematic bands that characterize, in these systems, the coexiste…

Data-driven quantitative modeling of bacterial active nematics Open

He Li, Xia-qing Shi, Mingji Huang, Xiaohong Chen, Minfeng Xiao , et al. · 2018

Significance Active nematics are nonequilibrium fluids consisting of elongated units driven at the individual scale. They spontaneously exhibit complex spatiotemporal dynamics and have attracted the attention of scientists from many discip…

Self-Propelled Rods: Linking Alignment-Dominated and Repulsion-Dominated Active Matter Open

Xia-qing Shi, Hugues Chaté · 2018

We study a robust model of self-propelled rods interacting via volume exclusion and show that its collective dynamics encompasses both that of the corresponding Vicsek-style model (where local alignment is the sole interaction), and motili…

Self-Propelled Particles with Velocity Reversals and Ferromagnetic Alignment: Active Matter Class with Second-Order Transition to Quasi-Long-Range Polar Order Open

Benoît Mahault, Xinchen Jiang, Éric Bertin, Yandong Ma, Aurelio Patelli , et al. · 2018

We introduce and study in two dimensions a new class of dry, aligning active matter that exhibits a direct transition to orientational order, without the phase-separation phenomenology usually observed in this context. Characterized by sel…

Fore-aft asymmetric flocking Open

Qiushi Chen, Aurelio Patelli, Hugues Chaté, Yu‐qiang Ma, Xia-qing Shi · 2017

We show that fore-aft asymmetry, a generic feature of living organisms and some active matter systems, can have a strong influence on the collective properties of even the simplest flocking models. Specifically, an arbitrarily weak asymmet…

Weak synchronization and large-scale collective oscillation in dense bacterial suspensions Open

Chong Chen, Song Liu, Xia-qing Shi, Hugues Chaté, Yilin Wu · 2017

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