SI2-SSE: A parallel computing framework for large-scale real-space and real-time TDDFT excited-states calculations

控制电子材料并了解其特性的能力一直是技术突破的驱动力。自20世纪60年代以来，电子器件的技术一直处于快速上升的轨道上，能够制造更小的硅晶体管（“摩尔定律”），今天的器件尺寸在纳米范围内。随着纳米技术的兴起，新兴材料的原子-原子量子模拟变得越来越重要，以可靠地补充当前的实验研究。原子系统的建模和模拟对于帮助众多工程师和科学家的日常工作至关重要，并且可以普遍影响跨越计算，传感和能源技术领域的广泛学科（工程，物理，化学和生物学）。该项目将加速量子技术的发展及其对全球经济的影响。一个新的软件将帮助捕捉许多基本的量子效应，这些效应在纳米技术中越来越重要，用于探索和原型制作新的革命性电子材料和器件。该项目旨在开发和提供一个新的开源软件NESSIE，可以解决材料和器件纳米工程应用中遇到的现代挑战。 NESSIE将使用最具成本效益的方法来执行激发态计算，时间相关密度泛函理论（TDDFT），结合数值算法和物理和数学建模技术的新组合。 NESSIE将能够在真实空间（使用有限元）和实时使用全电势（全电子）进行激发态TDDFT计算。一个新的分层并行化策略将允许NESSIE在这个理论水平上处理前所未有的原子有限大小系统。该项目的成果将为解决实时TDDFT激发态计算中的数值挑战开辟新的视角，以操作全范围的电子光谱学，并研究任意复杂分子和超大规模有限尺寸纳米结构中的纳米多体效应。预计NESSIE软件和相关的数值组件将成为科学界的一个新的有价值的新工具，可以应用于研究许多纳米结构材料的基本电子特性。该项目得到了计算机信息科学与工程局高级网络基础设施办公室和数学与物理科学局材料研究司的支持。

The ability to control electronic materials and understand their properties has been a driving force for technological breakthroughs. The technology for electronic devices has been on a rapidly rising trajectory since the 1960s with the ability to fabricate ever smaller silicon transistors (`Moore's Law'), with today's device sizes in the nanometer range. With the rise of nanotechnology, atom-by-atom quantum simulations of emerging materials are becoming increasingly important to reliably supplement the current experimental investigations. Modeling and simulations of atomic systems are essential to assist the everyday work of numerous engineers and scientists and can universally impact a wide range of disciplines (engineering, physics, chemistry, and biology) spanning the technological fields of computing, sensing and energy. This project will accelerate the development of quantum technologies and their impacts in the global economy. A new software will be produced to help capture many fundamental quantum effects which are increasingly important in nanotechnology for exploring and prototyping new revolutionary electronic materials and devices.This project aims at developing and offering a new open source software, NESSIE, that can address the modern challenges encountered in material and device nano-engineering applications. NESSIE will use the most cost-effective method to perform excited states calculations, the time-dependent density functional theory (TDDFT), in conjunction with a novel combination of numerical algorithms and physical and mathematical modeling techniques. NESSIE will be capable of performing excited-state TDDFT calculations using full-potential (all-electron) in real-space (using finite element) and real-time. A new hierarchical parallelization strategy will allow NESSIE to tackle unprecedented atomistic finite size systems at this level of theory. The outcome of this project will open new perspectives for addressing the numerical challenges in real-time TDDFT excited-states calculations to operate the full range of electronic spectroscopy, and study the nanoscopic many-body effects in arbitrary complex molecules and very large-scale finite-size nanostructures. It is expected that the NESSIE software and associated numerical components will become a new valuable new tool for the scientific community, that could be applied to investigate the fundamental electronic properties of numerous nanostructured materials.This project is supported by the Office of Advanced Cyberinfrastructure in the Directorate for Computer & Information Science and Engineering and the Division of Materials Research in the Directorate of Mathematical and Physical Sciences.