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使用 tikz-package 确定费曼图中线条的方向

tag-icon • tag-icon feynman tikz-feynman
使用 tikz-package 确定费曼图中线条的方向

考虑以下使用 tikz-feynman 包的代码：

\feynmandiagram [baseline={(current bounding box.center)},medium, vertical=b to f] {
        a [nudge=(-30:5mm)]
        -- [photon, edge label=\(p_{1}\)] b [label=190:\(\mu_{1}\)]
        -- [fermion, edge label=\(k+p_{1}\)] c,
        d[nudge=(220:5mm)] -- [photon, edge label'=\(p_{2}\)] c [label=-30:\(\mu_{2}\)],
        c -- [fermion, edge label=\(k+p_{1}+p_{2}\)] e [label=10:\(\mu_{3}\)] -- [fermion, edge label=\(k-p_{4}\)] f [label=176:\(\mu_{4}\)] -- [ fermion, edge label=\(k\)] b,
        g [nudge=(150:5mm)] -- [photon, edge label=\(p_{3}\)] e,
        h [nudge=(30:5mm)] -- [photon, edge label'=\(p_{4}\)] f,
    };

这给了我们图表

我想修改代码来翻转垂直线以获得下图

同时保持第一张图上的标签完好无损。我该怎么做？

答案1

我已经调整了我制作的示例你问的另一个问题。我没有在这里添加推动以使代码更清晰一些（但您可以轻松地将其添加回来）。

我还擅自清理了图表的创建方式，希望您不介意：）这应该会使它更简单、更容易。

现在，该算法默认会避免线条交叉。因此，要绘制所需的图表，您必须手动指定顶点的位置或分两步完成。我在下面展示了如何分两步完成，并且我在代码中进行了注释以解释各部分的作用。我希望这很清楚，但如果您需要一些说明，请随时发表评论。

原来，费米子线不相交

费米子线交叉

\documentclass[tikz,border=10pt]{standalone}

\usepackage[compat=1.1.0]{tikz-feynman}

\begin{document}
\feynmandiagram [
    baseline={(current bounding box.center)},
    vertical'=a to b,
  ] {
  %% Instead of having to specify `fermion` over and over, group them
  %% together.
  {[edges={fermion}]
    a -- [edge label'=\(k_{1}\)] b [label=0:\(\mu_{2}\)]
      -- [edge label'=\(k_{2}\)] c [label=-180:\(\mu_{3}\)]
      -- [edge label'=\(k_{3}\)] d [label=-180:\(\mu_{4}\)]
      -- [edge label'=\(k_{4}\)] a [label=0:\(\mu_{1}\)],
  },
  {[edges={photon}]
    %% Sometimes, the algorithms gets stuck when trying to figure out the final
    %% layout, hence why I'm switching the order of d and c below.
    a -- ap [particle=\(p_{1}\)],
    b -- bp [particle=\(p_{2}\)],
    d -- dp [particle=\(p_{4}\)],
    c -- cp [particle=\(p_{3}\)],
  },
};

\begin{tikzpicture}[baseline={(current bounding box.center)}]
  \begin{feynman}
    %% Just like before, we create the internal box of fermion lines, but this
    %% time we use `draw=none` so they are invisible.
    \diagram [vertical'=a to b] {
      {[edges={draw=none}]
        a -- b [label=0:\(\mu_{2}\)]
          -- c [label=-180:\(\mu_{3}\)]
          -- d [label=-180:\(\mu_{4}\)]
          -- a [label=0:\(\mu_{1}\)],
      },
      {[edges={photon}]
        %% Sometimes, the algorithms gets stuck when trying to figure out the final
        %% layout, hence why I'm switching the order of d and c below.
        a -- ap [particle=\(p_{1}\)],
        b -- bp [particle=\(p_{2}\)],
        d -- dp [particle=\(p_{4}\)],
        c -- cp [particle=\(p_{3}\)],
      },
    };

    %% We now need to add in the fermion lines.  Since we just want to connect
    %% existing vertices, we use the `\diagram*` command.  The parentheses are
    %% important as it tells the algorithm that these vertices exist already
    %% (instead of trying to create new ones).
    \diagram* {
      (a) -- [fermion] (b)
          -- [fermion] (d)
          -- [fermion] (c)
          -- (a),  %% No fermion line hear as it looks weird with the two arrows
                   %% overlapping.
    };
  \end{feynman}
\end{tikzpicture}
\end{document}

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