Developing Thermal Hybrid Exchange-Correlation Functionals for Accurate Prediction of Transport and Optical Properties of Warm Dense Plasmas

诺贝尔奖获得者密度泛函理论(DFT)方法已被广泛应用于更好地理解自然的物理和化学，以及改善我们的日常生活的重要应用。DFT应用的例子从发明特定功能的材料，到了解化学反应以获得更好的产品，再到设计治疗癌症的药物。DFT的成功依赖于材料中粒子如何相互作用的近似精度，即所谓的交换关联(XC)自由能密度泛函。到目前为止，大多数可用的XC泛函都局限于零温度情况。在本研究项目中，将开发有限温度XC泛函，以显著提高密度泛函在等离子体物理和材料研究中的预测能力。预计这一研究项目的成果将在行星科学、天体物理学、聚变能源和国防应用等各种科学领域和应用领域产生重大影响，并通过提供发现更好的材料和设计有效药物的工具对社会产生积极影响。在温暖稠密的条件下，物质广泛存在于宇宙中--从实验室产生的冲击和惯性约束聚变内爆，到行星核心和棕矮星和白矮星等天体物理对象。彻底了解热致密物质、非理想等离子体和“奇异”等离子体的性质，是揭开行星和天体物理科学中许多谜团的关键；例如，可能的H-He在土星上的分离。要可靠地预测物质在这种极端条件下的输运和光学性质，很大程度上取决于DFT方法所要求的XC泛函的精度。在这个项目中，将建立一个三步研究计划来开发精确的有限温度混合XC泛函：(I)评估可用的热自由能泛函性能，以确定这些当前泛函失效的状态条件；(Ii)开发与那些被证明在零温情况下的能隙准确对应的热混合和热筛选混合XC泛函；以及(Iii)将开发的热混合XC泛函应用于温密等离子体模拟，以实验为基准，并向广泛的计算科学界提供有用的软件。特别是，PI将以开源形式发布生成的软件包，并将其合并到现有Quantum-Espresso和ABINIT计算软件包的标准分发中。这将使该项目有更广泛的增长。这方面对高级网络基础设施办公室的软件集群特别感兴趣，该办公室为该奖项提供了共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Nobel Prize-winning method of density-functional theory (DFT) has been widely used for important applications to better understand the physics and chemistry of nature, as well as to improve our daily life. Examples of DFT applications range from inventing materials of specific functions, to understanding chemical reactions for better products, to designing drugs to cure cancers. The success of DFT relies on the accuracy of the approximation of how particles in a material interact with each other, the so-called exchange-correlation (XC) free-energy density functional. So far, most of the available XC-functionals have been limited to zero-temperature cases. In this research project, finite-temperature XC-functionals will be developed to significantly improve the predictive capability of DFT for plasma-physics and materials studies. The outcome of this research project is expected to make a significant difference in a variety of scientific fields and applications such as planetary science, astrophysics, fusion-energy and national defense applications, as well as to make a positive impact on the society through delivering tools for discovering better materials and designing efficient drugs.Matter at warm dense conditions exists vastly in the universe -- from shocks and inertial confinement fusion implosions created in laboratories to planetary cores and astrophysical objects such as brown and white dwarfs. Thorough understanding of the properties of warm-dense matter, non-ideal and "exotic" plasmas hold the key to unravel many mysteries in planetary and astrophysical sciences; for example, the possible H-He demixing on Saturn. Reliably predicting the transport and optical properties of matter at such extreme conditions heavily depends on the accuracy of XC functionals required by the DFT method. In this project, a three-step research program will be established to develop accurate finite-temperature hybrid XC-functionals by: (i) Assessing the available thermal free-energy functional performance to identify the state conditions wherein those current functionals fail; (ii) Developing thermal-hybrid and thermal-screened hybrid XC functionals that correspond to those proven to be accurate for the energy gap in the zero-temperature case; and (iii) Applying the developed thermal hybrid XC-functionals to warm-dense-plasma simulations to benchmark with experiments and deliver a useful software to the broad computational science community. In particular, the PIs will release the resulting software package as open source and incorporate it into the standard distribution for the existing Quantum-Espresso and ABINIT computational packages. This will allow a wider growth of the project. This aspect is of special interest to the software cluster in the Office of Advanced Cyberinfrastructure, which has provided co-funding for this award.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.