Information flow and irreversibility in self-organised active matter

最近的许多研究都致力于揭示活性物质的随机热力学；具体地通过波动熵产生量化主动动力学的时间反转对称性破缺，并将熵产生与能量量联系起来，如“活动”的散热和能量成本。对于单个活跃粒子，最初的研究已经证明，时间不可逆性和能量学可以通过使用信息理论测量相互联系。但到目前为止，这一观点尚未应用于集体主动系统。在此基础上，提出了集体活性物质的信息热力学。为此，我们分析了两种通用模型（基于粒子的模型和活动场模型）中发生了什么样的信息流，它们具有什么样的空间方向，以及它们如何反映自组织的集体状态以及有序和无序之间的相变。我们进一步的目标是将信息流与能量和热力学措施联系起来，特别是局部熵的产生，通过采用和扩展先前开发的信息热力学框架来描述受反馈控制的系统的物理。特别是，我们旨在建立具有连续信息流的广义第二定律，用于活性物质的局部熵产生。结合随机热力学、信息论、控制论、活性物质、相变等概念，创新地针对活性物质随机热力学以及主动自组织（如群体形成）等开放性研究问题。它可能会进一步为一种新型的独立于模型的集体动力学研究铺平道路。因此，这些结果对其他领域的集体非平衡系统也很重要，例如生物物理学和计算机科学。

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.