标题： 奇异粘性扩散流体 显示英文标题

标题： Odd Viscodiffusive Fluids

摘要： 我们引入了一种“奇粘扩散流体”的理论，这些流体通过粘性和扩散传输的耦合表现出三维奇传输现象。 在这些流体中，扩散通量可能来源于正交速度梯度，反之，应力可能来源于浓度梯度。 我们使用最近提出的“通量假设”来研究微观涨落，以推导控制传输系数的格林-库博关系和互易关系。 这些关系表明，为了观察这些耦合，只需在微观尺度上破坏宇称对称性，而不需要破坏时间反演对称性。 因此，手性液体，无论是被动的还是主动的，都是粘扩散流体的自然选择。 然后，我们介绍了两个分析上可处理的模型系统，即一个生成器和一个相应的互易引擎，它们展示了手性物质中的粘扩散交叉耦合的性质，并使实验测量新型传输系数成为可能。 最后，我们论证了手性细菌悬浮液应被视为奇粘扩散流体，并利用我们的理论预测了先前实验微流体研究中细菌在剪切流作用下的迁移行为。 显示英文摘要

摘要： We introduce a theory of "odd viscodiffusive fluids," which exhibit three-dimensional odd transport phenomena through the coupling of viscous and diffusive transport. In these fluids, diffusive fluxes may arise from orthogonal velocity gradients and, reciprocally, stresses may arise from concentration gradients. We examine microscopic fluctuations using the recently proposed "flux hypothesis" to derive Green-Kubo and reciprocal relations for the governing transport coefficients. These relations suggest that only parity symmetry, and not time-reversal symmetry, must be broken at the microscopic scale to observe these couplings. Chiral liquids, whether passive or active, are therefore a natural choice as viscodiffusive fluids. We then introduce two analytically tractable model systems, namely a generator and a corresponding reciprocal engine, which illustrate the nature of viscodiffusive cross-coupling in chiral matter and enable the experimental measurement of the novel transport coefficients. Finally, we make the case for chiral bacterial suspensions to be odd viscodiffusive fluids, and use our theory to predict the behaviors exhibited in prior experimental microfluidic studies involving bacterial migration in response to shearing flows.