Dynamics and thermodynamics in artificial and natural active systems with delay

主动自我推进是赋予生物体进化优势的重要特征之一。然而，由原始形式的单细胞生命（如细菌和精子细胞）所利用的自我推进技术已经相当复杂。它们的鞭毛跳动或动态的身体形状变化需要简化模型来掌握它们集体运动的物理原理。另一方面，最近的实验和技术进步提供了大量的人工微泳者，它们可以被激活，甚至以一种很好理解和控制的方式操纵。我们现在可以赋予它们越来越复杂的物理和虚拟相互作用，使我们能够在自下而上的方法中模仿在生活世界中观察到的新兴复杂性。特别是，我们可以故意设计理论上易于处理的实验系统，而理想化的理论预测有望产生有趣的集体行为，可以指导实验设计。这一战略是本提案的核心，旨在促进实验、分析理论和计算机模拟之间的密切合作。我们的重点将主要是自组织和动态缩放的相互作用的游泳者/没有限制，构象熵和信息通量，以及被动探针在活性物质环境。作为一个重要的创新方面，我们希望系统地研究时滞相互作用的作用。长期目标是为正在进行的越来越普遍和统一的粗粒度动态和热力学描述的活性物质的概念里程碑和范式模型系统。

Active self-propulsion is one of the important traits giving living organisms an evolutionary edge. Already the self-propulsion techniques harnessed by primitive forms of unicellular life, such as bacteria and sperm cells, are quite complicated, though. Their beating flagella or dynamic body shape changes call for simplified models to grasp the physical principles of their collective motion. On the other hand, recent experimental and technological progress has supplied a large arsenal of artificial microswimmers that can be activated and even steered in a well-understood and well-controlled way. We can now endow them with increasingly sophisticated physical and virtual mutual interactions that enable us to mimic the emerging complexity observed in the living world, within a bottom-up approach. In particular, we can deliberately design experimental systems that are theoretically tractable, and idealized theoretical predictions promising interesting collective behavior can guide the experimental design. This strategy is at the heart of the present proposal, which aims to foster a close collaboration between experiment, analytical theory and computer simulations. Our focus will mostly be on self-organization and dynamical scaling of interacting swimmers with/without confinement, conformational entropy and information fluxes, and passive probes in active-matter environments. As an important innovative aspect, we want to systematically investigate the role of time-delayed mutual interactions. The long-term goal is to contribute conceptual milestones and paradigmatic model systems for an ongoing increasingly general and unified coarse-grained dynamic and thermodynamic description of active matter.