论文标题
重新定义的真空途径和量规不变子集，用于带价电子的封闭壳系统的两光子交换图
Redefined vacuum approach and gauge-invariant subsets in two-photon-exchange diagrams for a closed-shell system with a valence electron
论文作者
论文摘要
研究了具有单价电子的原子的两光子交换图。利用重新定义真空形式主义的严格结合状态QED框架内的任意状态得出了计算公式。与其他方法相反，重新定义的真空方法可以识别八个规数不变的子集，因此有效地检查了获得的结果的一致性。在分析中（对于任意状态）以及对于2s，2p1/2和2p3/2价电子中的2s，2p1/2和2p3/2价电子，都在分析上证明了发现子集的规格不变性。在提出方法的框架中识别量规不变子集为解决更复杂的图（例如，三光子交换）打开了一种方法，在更简单的子集上的碎片对于成功计算至关重要。
The two-photon-exchange diagrams for atoms with single valence electrons are investigated. Calculation formulas are derived for an arbitrary state within the rigorous bound-state QED framework utilizing the redefined vacuum formalism. In contrast to other methods, the redefined vacuum approach enables the identification of eight gauge-invariant subsets and, thus, efficiently checks the consistency of the obtained results. The gauge invariance of found subsets is demonstrated both analytically (for an arbitrary state) as well as numerically for 2s, 2p1/2, and 2p3/2 valence electrons in Li-like ions. Identifying gauge-invariant subsets in the framework of the proposed approach opens a way to tackle more complex diagrams, e.g., three-photon exchange, where the fragmentation on simpler subsets is crucial for its successful calculation.
