OAC Core: Small: Efficient and scalable tools for design and analysis of active matter systems

“活性物质”一词指的是一类新型的非平衡材料，由自驱动的成分组成，通过将环境中的能量（通常是化学能）转化为机械功（运动或游泳）来提供动力。它们在自然界中是丰富的，从有生命的到无生命的;这个术语可以用来描述成群的鸟类或成群的细菌，它们自组织成化学活性的胶体颗粒。活动物质的共同特征是集体运动、反常涨落和平衡物理学无法解释的力学性质。到目前为止，大多数研究都是在小系统或有限数量的粒子上进行的，目的是用过于简化的属性描述符来理解潜在的行为。该项目旨在开发一个框架，使人们能够理解和利用活性物质系统的特性;为了实现这一工程飞跃，项目团队打算开发一个公开的虚拟实验室，快速活性物质模拟器（FAMS），这将使新型活性物质系统的原型通过有效的离散粒子方法。为了实现广泛传播，该项目将创建本地K-12外展计划，利用REU为本科生提供的机会，招募代表性不足的学生，并将计算技术纳入我们的本科和研究生课程。拟议的研究将改变活性物质研究的最新技术，从理解简单的规范系统到设计工具，使工程/操纵活性物质来构建系统。要做到这一点，人们需要考虑粒子的形态，周围环境，外力等，因为问题本质上是多尺度的，人们需要开发严格的方法，在这些尺度上是有效的，并充分解决了长距离和短距离的相互作用，通过将粒子形状的细节，复杂的几何形状的障碍物，和限制边界。为实现上述目标，项目组将在四个不同领域进行研究和开发;（a）通过等几何方法对几何形状和几何形状上的物理学进行高阶表示，以便保证保真度而不需要高成本，（B）将这些表示铸造在基于边界积分方程的框架内，（c）结合一套加速技术，以减少内存和计算瓶颈，从而促进对实际聚合物的分析，以及（d）与现有库集成以利用线性代数（密集和稀疏）的并行算法。该项目将使用这个框架来表征材料特性和集体动力学。这些新方法将改变活跃物质研究的最新技术，从理解简单的规范系统到构建工具，使活跃物质的工程/操纵能够构建虚拟的“生命”系统。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

The term "active matter" denotes a novel class of non-equilibrium materials made up of constituents that are self-driven, powered by converting the energy in the environment (typically chemical energy) to mechanical work (locomotion or swimming). They are abundant in nature, from the animate to the inanimate; this terminology can be used to describe flocks of birds or swarms of bacteria that self-organize to chemically active colloidal particles. The common characteristics of active matter are collective motion, anomalous fluctuations, and mechanical properties that cannot be explained by equilibrium physics. To date, most studies have been on small systems or a limited number of particles with the goal of understanding the underlying behavior with over-simplified property descriptors. This project seeks to develop a framework that will enable both understanding and exploiting the properties of active matter systems; to take this engineering leap forward, the project team intends to develop a publicly available virtual laboratory, the Fast Active Matter Simulator (FAMS), that will enable prototyping of novel active matter systems via efficient discrete particle methods. To enable widespread dissemination, the project will create local K-12 outreach programs, leverage REU opportunities for undergraduate students, recruit under-represented students, and incorporate computational techniques into our undergraduate and graduate curriculum. The proposed research will transform the state-of-the-art in active matter research, from understanding simple canonical systems to design tools that would enable engineering/manipulation of active matter to build systems. To do so, one needs to account for the morphology of particles, ambient environment, external forces, etc. As the problem is inherently multiscale, one needs to develop rigorous methods that are efficient across these scales, and fully resolve the long- and short-range interactions by incorporating the details of particle shapes, complex geometries of obstacles, and confinement boundaries. To realize the above objectives, the project team will perform research and development in four different areas; (a) higher-order representation of both geometry and physics on the geometry via isogeometric methods so as to guarantee fidelity without high cost, (b) casting these representations within a boundary integral equation based framework, (c) integrating with a set of acceleration techniques to reduce memory and computational bottlenecks to facilitate analysis of realistic aggregates, and (d) integration with existing libraries to leverage parallel algorithms for linear algebra (dense and sparse). The project will use this framework to characterize material properties and collective dynamics. These new methods will transform the state-of-the-art in active matter research, from understanding simple canonical systems to building tools that would enable engineering/manipulation of active matter to build virtual “living” systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.