论文标题
建立密度或绿色功能功能功能的功能的策略：我们可以学到什么？
Strategies to build functionals of the density, or functionals of Green's functions: what can we learn?
论文作者
论文摘要
总体上不能准确解决多体问题，最突出的近似值之一是构建扰动扩展。可以进行各种扩展，这会因要扩展的数量，扩展变量，起点和想法如何恢复或终止系列而有所不同。尽管已经讨论了很多，并且已经做了很多事情，但出于历史原因，尤其是有限的计算或存储能力，做出了一些选择。目前的工作旨在通过比较基于\ gf s的功能成分以及另一侧的电荷密度来检查不同情况下做出的不同选择的理由。特别有趣的是，如何建立一个最佳的起点，以近似非本地数量，利用近视或远见，并大胆地考虑模型以外的均质电子气体。这将包括使用连接器近似值。我们还将讨论为什么构建密度的功能是一个好主意。
The many-body problem can in general not be solved exactly, and one of the most prominent approximations is to build perturbation expansions. A huge variety of expansions is possible, which differ by the quantity to be expanded, the expansion variable, the starting point, and ideas how to resum or terminate the series. Although much has been discussed and much has been done, some choices were made for historical reasons, in particular, limited computation or storage capacities. The present work aims at examining the justifications for different choices made in different contexts, by comparing ingredients of functionals based on \GF s on one side, and on the charge density on the other side. Of particular interest will be the question of how to build an optimal starting point for the approximation of non-local quantities, making use of near- or far-sightedness, and daring to consider models beyond the homogeneous electron gas. This will include the use of connector approximations. We will also discuss why it is a good idea to build functionals of the density.
