Information flow and irreversibility in self-organised active matter

最近的许多研究都致力于解开活动物质的随机热力学；特别是通过脉动的熵产生来量化活动动力学的时间逆对称破缺，并将熵产生与能量量联系起来，如活动的热耗散和能量成本。对于单个活性粒子，最初的研究已经证明，时间不可逆性和能量学可以通过信息理论的方法相互联系。但到目前为止，这一观点还没有应用于集体主动系统。通过这个提议，我们的目的是提出集体活性物质的信息热力学。为此，我们在两个一般模型(基于粒子的模型和活动场模型)中分析了发生什么类型的信息流，它们具有什么空间方向，以及它们如何反映自组织的集体态以及有序和无序之间的相变。我们的进一步目标是通过采用和扩展信息热力学框架来将信息流与能量和热力学措施，特别是局部熵产生联系起来，信息热力学框架以前是用来描述受反馈控制的系统的物理的。具体地说，我们的目标是建立具有连续信息流的活性物质局部熵产生的广义第二定律。通过结合随机热力学、信息论、控制论、活性物质和相变的概念，这一提议以一种创新的方式瞄准了关于活性物质的随机热力学以及活跃的自组织(如群体形成)的公开研究问题。这可能会进一步为一种新型的模型无关的集体动力学调查铺平道路。因此，这些结果对生物物理学和计算机科学等其他领域的集体非平衡系统也具有重要意义。

A lot of recent research is devoted to unravel the stochastic thermodynamics of active matter; specifically quantifying the time- reversal symmetry breaking of active dynamics by the fluctuating entropy production, and connecting the entropy production to energetic quantities, like the heat dissipation and energetic cost of the 'activity'. For individual active particles, first studies have demonstrated that time-irreversibility and energetics can be linked with each other by using information-theoretical measures. But so far this perspective has not been applied to collective active systems. With this proposal we aim to put forward the information- thermodynamics of collective active matter. To this end, we analyse in two generic models (a particle-based and an active field model) what kind of information flows occur, which spatial direction they have, and how they reflect the self-organised collective states as well as phase transitions between order and disorder. We further aim to connect the information flow with energetic and thermodynamic measures, specifically the local entropy production, by employing and extending the framework of information- thermodynamics that was previously developed to describe the physics of systems subject to feedback control. In particular, we aim at establishing generalised second laws with continuous information flow for the local entropy production of active matter. By combining concepts from stochastic thermodynamics, information theory, control theory, active matter, and phase transitions, this proposal targets in an innovative way open research questions concerning the stochastic thermodynamics of active matter, as well as active self-organization, e.g., swarm formation. It may further pave the way for a novel type of model-independent investigation of collective dynamics. The results will thus also be of importance for collective nonequilibrium systems in other fields, such as biophysics and computer science.