标题： 标量活性湍流中的不可逆性：拓扑缺陷的作用 显示英文标题

标题： Irreversibility in scalar active turbulence: The role of topological defects

摘要： 在许多主动系统中，游泳者集体搅动周围流体以稳定一些自维持的涡旋。 由此产生的非平衡状态通常被称为主动湍流，这是与被动流体在外力搅拌下的湍流相类比。 尽管主动湍流显然远离平衡，但要确定哪些涌现特征主要控制偏离平衡可逆动力学的情况可能具有挑战性。 在这里，我们揭示出动力学不可逆性本质上源于主动应力中的奇点。 具体来说，考虑到游泳者密度和流函数的耦合动力学，我们证明了缺陷周围的涡旋流动对称性决定了整体的不可逆性。 我们的详细分析导致识别出缺陷对的具体配置是不可逆性的主要贡献。 显示英文摘要

摘要： In many active systems, swimmers collectively stir the surrounding fluid to stabilize some self-sustained vortices. The resulting nonequilibrium state is often referred to as active turbulence, by analogy with the turbulence of passive fluids under external stirring. Although active turbulence clearly operates far from equilibrium, it can be challenging to pinpoint which emergent features primarily control the deviation from an equilibrium reversible dynamics. Here, we reveal that dynamical irreversibility essentially stems from singularities in the active stress. Specifically, considering the coupled dynamics of the swimmer density and the stream function, we demonstrate that the symmetries of vortical flows around defects determine the overall irreversibility. Our detailed analysis leads to identifying specific configurations of defect pairs as the dominant contribution to irreversibility.