近日，德国斯图加特大学的Thomas Speck及其研究团队取得一项新进展。经过不懈努力，他们通过行带的相和质量输运耦合揭示了手性活性流体中的集体霍尔电流。相关研究成果已于2024年6月28日在国际知名学术期刊《美国科学院院刊》上发表。

该研究团队报道了计算机模拟中发现的（元）稳定行带现象。这些行带独特于极性群，它们通过耦合相位与质量输运，诱导产生带有垂直于传播方向分量的体积粒子电流，进而引发集体霍尔（或马格努斯）效应。行带的形成需要足够小的轨道，而在轨道半径较大的情况下，它们会经历非连续跃迁至同步状态。

在最小流体力学理论的框架下，研究人员揭示了这些行带可以视为完全基于数值观测性质的非色散孤子解。

据悉，由不断远离热平衡的成分组成的活性流体可以支持自发电流，并且可以设计成具有非常规的输运特性。

附：英文原文

Title: Collective Hall current in chiral active fluids: Coupling of phase and mass transport through traveling bands

Author: Siebers, Frank, Bebon, Robin, Jayaram, Ashreya, Speck, Thomas

Issue&Volume: 2024-6-28

Abstract: Active fluids composed of constituents that are constantly driven away from thermal equilibrium can support spontaneous currents and can be engineered to have unconventional transport properties. Here, we report the emergence of (meta)stable traveling bands in computer simulations of aligning circle swimmers. These bands are different from polar flocks and, through coupling phase with mass transport, induce a bulk particle current with a component perpendicular to the propagation direction, thus giving rise to a collective Hall (or Magnus) effect. Traveling bands require sufficiently small orbits and undergo a discontinuous transition into a synchronized state with transient polar clusters for large orbital radii. Within a minimal hydrodynamic theory, we show that the bands can be understood as nondispersive soliton solutions fully accounting for the numerically observed properties.

DOI: 10.1073/pnas.2320256121

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2320256121

来源：科学网 小柯机器人