论文标题
骨骼图表技术的误导性收敛：找到正确的解决方案时
Misleading convergence of the skeleton diagrammatic technique: when the correct solution can be found
论文作者
论文摘要
自洽的骨骼图解技术（SDT）的融合（通过以本身的方式求和Feynman图来确定完整的绿色功能 - 与错误的答案有关，与存在的非扰动分支的存在有关。尽管在不知道确切结果的情况下可以检测到误导性收敛性，但在发生这种情况的制度中，SDT仍然不适用。我们表明，误导性收敛并不总是排除恢复精确解决方案。除了既定的机制外，SDT与错误答案的收敛可能源于固有的图表系列的差异，这使我们能够基于控制分析延续来通过修改的SDT协议恢复精确的解决方案。我们通过将其应用于可解决的（0+0）D Hubbard模型，Hubbard Atom和2D Hubbard模型中的分析方法来说明这种方法。
Convergence of the self-consistent skeleton diagrammatic technique (SDT) -- in which the full Green's function is determined through summation of Feynman diagrams in terms of itself -- to the wrong answer has been associated with the existence of non-perturbative branches of the Luttinger-Ward functional. Although it has been possible to detect misleading convergence without the knowledge of the exact result, the SDT has remained inapplicable in the regimes where this happens. We show that misleading convergence does not always preclude recovering the exact solution. In addition to the established mechanism, convergence of the SDT to the wrong answer can stem from divergence of the inherent diagrammatic series, which allows us to recover the exact solution by a modified SDT protocol based on controlled analytic continuation. We illustrate this approach by its application to the analytically solvable (0+0)d Hubbard model, the Hubbard atom, and the 2d Hubbard model in a challenging strong-coupling regime, for which the SDT is solved with controlled accuracy by the diagrammatic Monte Carlo (DiagMC) technique.
