标题： 三维手性活性流体中的奇异密度关联 显示英文标题

标题： Singular density correlations in chiral active fluids in three dimensions

摘要： 我们通过使用一种简单的螺旋自推进粒子模型，研究三维手性活性流体中的密度涨落。 每个粒子由自推进力和恒定的单轴手性扭矩驱动，所有粒子的方向相同。 由于粒子运动的螺旋特性，即使系统在空间上是均匀的，它也是普遍各向异性的。 数值模拟表明，螺旋度在低波数极限下会在静态结构因子（傅里叶空间中的密度关联函数）中诱导各向异性图案和奇异性。 此外，在无限持续时间极限下，系统在与手性扭矩垂直的方向上表现出超均匀性，而在平行方向上则出现巨大的密度涨落。 随后，我们为该系统构建了一个波动流体动力学理论，以描述奇异行为。 所得方程的线性分析给出了静态结构因子的解析表达式，其定性地与我们的数值结果一致。 显示英文摘要

摘要： We investigate density fluctuations in three-dimensional chiral active fluids by using a simple particle model of helical self-propelled particles. Each particle is driven by a self-propelled force and a constant uniaxial chiral torque, whose direction is identical for all particles. Due to the helical nature of the particle motion, the system is generically anisotropic even when it is spatially homogeneous. Numerical simulations demonstrate that the helicity induces an anisotropic pattern and a singularity in the static structure factor (the density correlation function in Fourier space) in the low-wavenumber limit. Moreover, the system in the limit of infinite persistence time exhibits hyperuniformity in the direction perpendicular to the chiral torque, while giant density fluctuations emerge along the parallel direction. We then construct a fluctuating hydrodynamic theory for the system to describe the singular behavior. A linear analysis of the resulting equations yields an analytical expression for the static structure factor, which qualitatively agrees with our numerical findings.