The GW approximation: content, successes and limitations,Wiley Interdisciplinary Reviews: Computational Molecular Science

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The GW approximation: content, successes and limitations
Wiley Interdisciplinary Reviews: Computational Molecular Science ( IF 16.8 ) Pub Date : 2017-12-27 , DOI: 10.1002/wcms.1344
Lucia Reining _{1,

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Affiliation

Many observables such as the density, total energy, or electric current, can be expressed explicitly in terms of the one‐body Green's function, which describes electron addition or removal to or from a system. An efficient way to determine such a Green's function is to introduce a self‐energy, which is a nonlocal and dynamic effective potential that influences the propagation of particles in an interacting system. The state‐of‐the art approximation for the self‐energy is the GW approximation, where the system to (or from) which the electron is added (or removed) is described as a polarizable, screening, medium. This is expressed by the name of the approximation: ‘GW’ stands for the one‐body Green's function G and for W, the dynamically screened Coulomb interaction. The GW approximation is very popular for the calculation of band structures in solids, and increasingly used also to describe nanostructures, clusters, and molecules. As compared to static mean‐field approximations for the effective potential, the dynamical screening of the Coulomb interaction in GW leads to a renormalization of energies, to broadening and/or to the observation of additional excitations. An analysis of the approximations that lead to the GW self‐energy, and of the underlying picture, explains the successes and the limitations of the approach.

中文翻译：

GW近似值：内容，成功与局限

许多可观测的事物，例如密度，总能量或电流，都可以用单体格林函数来明确表示，该函数描述了电子向系统中的添加或去除。确定这种格林函数的一种有效方法是引入自能量，这是一种非局部的，动态的有效电势，会影响相互作用系统中粒子的传播。自能的最新技术近似是GW近似，其中电子被添加（或去除）的系统被描述为可极化的屏蔽介质。这由近似名称表示：'GW'代表单身格林函数G并代表W，即动态筛选的库仑互动。GW近似法非常适用于计算固体中的能带结构，并且越来越多地用于描述纳米结构，簇和分子。与有效势的静态均值近似相比，对GW中库仑相互作用的动态筛选导致能量重新归一化，拓宽和/或观察到其他激发。对导致GW自能的近似方法和基本情况的分析，解释了该方法的成功之处和局限性。

更新日期：2017-12-27

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