Compact wave function methods for chemical systems

化学部的化学理论、模型和计算方法项目支持哈佛大学的Alan Aspuru-Guzik博士开发一种高效、准确的方法来研究现有方法难以研究的分子和固体的电子结构。化学和物理领域的计算和数据驱动科学与工程项目，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难以解决的。用现有计算机对实际相关尺寸的系统进行精确的计算描述仍然是一个挑战。如果可用，准确的描述承诺在材料设计周期的变革性加速。本文通过借鉴信号处理领域的思想，为原子、分子和材料的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软件包中。在这个项目中开发的想法和软件将被整合到一个名为“量子世界”的大型开放在线课程（MOOC）中，这是Aspuru-Guzik在HarvardX平台上开发的。借鉴信号处理领域的匹配追踪技术，将其与非正交轨道展开相结合。初步结果表明，该方法与目前最先进的方法具有竞争力，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推进所提出的方法，即非正交多分量自适应贪婪迭代压缩（NOMAGIC）。NOMAGIC已经表现出优异的波函数压缩，其数量级为几十个行列式，可以获得精确的化学解。Aspuru-Guzik和同事正在开发NOMAGIC方法，将其作为一种黑盒方法，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，并将该方法所考虑的问题扩展到张量网络。

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.