Mitxelena I, Piris M, Rodríguez-Mayorga M
Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain. Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), 20018 Donostia, Euskadi, Spain.
J Phys Condens Matter. 2017 Oct 25;29(42):425602. doi: 10.1088/1361-648X/aa80ca. Epub 2017 Jul 19.
Strongly correlated materials are now under intense development, and natural orbital functional (NOF) methods seem to be able to capture the physics of these systems. We present a benchmark based on the Hubbard model for a class of commonly used NOF approximations (also known as reduced density matrix functional approximations). Our findings highlight the importance of imposing ensemble N-representability conditions in order to obtain consistent results in systems with either weak or strong electronic correlation, such as the Hubbard system with a varying two-particle interaction parameter. Based on the accuracy of the results obtained using PNOF7, which retrieves a large amount of the total strong nondynamic correlation, the Hubbard model points out that N-representability gives solid foundations for NOF development.
强关联材料目前正处于深入研究阶段，自然轨道泛函（NOF）方法似乎能够捕捉这些体系的物理性质。我们基于哈伯德模型对一类常用的NOF近似（也称为约化密度矩阵泛函近似）进行了基准测试。我们的研究结果强调了施加系综N可表示性条件的重要性，以便在具有弱或强电子关联的体系中获得一致的结果，例如具有可变双粒子相互作用参数的哈伯德体系。基于使用PNOF7获得的结果的准确性，PNOF7能够恢复大量的总强非动态关联，哈伯德模型指出N可表示性为NOF的发展提供了坚实的基础。
