Compact wave function methods for chemical systems

化学系的化学理论、模型和计算方法项目获得这一奖项，支持哈佛大学的Alan Aspuru-Guzik博士开发一种高效而准确的方法来研究分子和固体的电子结构，而现有方法很难研究这些结构。化学和物理领域的计算和数据支持的科学和工程计划，以及CISE/ACI CIF21软件重用风险基金将为该奖项做出贡献。原子、分子和固体的电子结构的精确量子力学描述在计算上是困难的。目前的计算机可以对实际相关的系统进行准确的计算描述，这仍然是一个挑战。如果可能，准确的描述有望在材料设计周期中加速变革。这项工作借鉴了信号处理领域的思想，为原子、分子和材料波函数的紧凑表示提出了一种新的思路。Aspuru-Guzik小组正在努力优化计算机代码，然后将其作为开源发布，并将其整合到流行的量子化学计算机包中。在这个项目中开发的想法和软件将被纳入一个大型开放在线课程(MOOC)中，名为《量子世界》，该课程是Aspuru-Guzik在嘉实X平台下开发的。借鉴了信号处理领域的一种技术--匹配追踪，并将其与非正交轨道展开相结合。初步结果表明，该方法与最先进的方法相比具有一定的竞争力，但仍需要大量的软件开发和理论扩展。本课题的主要目标是提出一种非正交多分量自适应贪婪迭代压缩方法(NOMAGIC)。NOMAGIC已经显示出数十个行列式的极佳波函数压缩，可获得化学上精确的解决方案。Aspuru-Guzik和他的同事正在开发NOMAGIC方法，作为一种黑匣子方法，将其与几个电子结构封装结合在一起。研究人员正在开发激发态模拟的方法，以及扩展张量网络方法所考虑的ANSAZ。

With this award, the Chemical Theory, Models and Computational Methods program in the Chemistry Division is supporting Dr. Alan Aspuru-Guzik of Harvard University to develop an efficient and accurate method to study the electronic structure of molecules and solids that are difficult to study by existing approaches. The Computational and Data-Enabled Science and Engineering programs in Chemistry and Physics, as well the CISE/ACI CIF21 Venture Fund for Software Reuse will contribute to the award. The exact quantum mechanical description of the electronic structure of atoms, molecules and solids is computationally intractable. Accurate computational descriptions that can be carried out with current computers for systems of practically relevant sizes remains a challenge. If available, accurate descriptions promise a transformative acceleration in the cycle of materials design. The proposed work advances a new idea for the compact representation of the wave functions of atoms, molecules and materials by borrowing ideas of the field of signal processing. The Aspuru-Guzik group is working to optimize the computer code, and then to release it both as open source and incorporated in popular quantum chemistry computer packages. The ideas and software developed in this project will be incorporated into a massive open online course (MOOC), entitled " The Quantum World", that Aspuru-Guzik is developing under the HarvardX platform. A technique borrowed from the field of signal processing, matching pursuit, is combined with a non-orthogonal orbital expansion. Preliminary results show that the method is competitive with the state-of-the-art methods but still requires considerable software development and theoretical extension. The main objective of the current project is to advance the proposed method, namely the non-orthogonal multicomponent adaptive greedy iterative compression (NOMAGIC). NOMAGIC already has shown excellent wave function compression of the order of tens of determinants for obtaining chemically accurate solutions. Aspuru-Guzik and coworkers are developing the NOMAGIC method as a black box method to be incorporated with several electronic structure packages. The researchers are developing methods for excited state simulation as well as to extend the ansatz considered by the approach to tensor networks.