基于格林函数理论的一种正则化二阶相关方法
A regularized second-order correlation method from Green's function theory
AI总结：
提出一种基于格林函数理论的单粒子框架，推导出准粒子MP2理论（QPMP2），有效避免了传统微扰理论在强相关体系中的发散问题，并成功应用于分子与Hubbard模型的相变研究。
摘要：
我们提出了一种可扩展的单粒子框架，受格林函数理论启发，用于处理分子和材料中的电子相关。通过引入Goldstone自能，我们从单粒子格林函数推导出一种具有尺寸广延性的Brillouin-Wigner微扰理论。这种新的基态相关能被称为准粒子MP2理论（QPMP2），它避免了在强相关体系中二阶Møller-Plesset微扰理论和Coupled Cluster Singles and Doubles中存在的特征性发散。我们证明QPMP2能精确重现Hubbard二聚体的基态能量和性质，并在六、八和十位点Hubbard模型中展示了该方法的优越性，其定性重现了金属到绝缘体的相变，而传统方法则彻底失败。我们将该形式体系应用于特征性强相关分子系统，表明QPMP2为MP2提供了一种高效且尺寸一致的正则化方法。
英文摘要：
We present a scalable single-particle framework to treat electronic correlation in molecules and materials motivated by Green's function theory. We derive a size-extensive Brillouin-Wigner perturbation theory from the single-particle Green's function by introducing the Goldstone self-energy. This new ground state correlation energy, referred to as Quasi-Particle MP2 theory (QPMP2), avoids the characteristic divergences present in both second-order Møller-Plesset perturbation theory and Coupled Cluster Singles and Doubles within the strongly correlated regime. We show that the exact ground state energy and properties of the Hubbard dimer are reproduced by QPMP2 and demonstrate the advantages of the approach for the six-, eight- and ten-site Hubbard models where the metal-to-insulator transition is qualitatively reproduced, contrasting with the complete failure of traditional methods. We apply this formalism to characteristic strongly correlated molecular systems and show that QPMP2 provides an efficient, size-consistent regularization of MP2.
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