答案1
免责声明:我是 Ti 的偶尔用户钾Z 和我完全没有用它画费曼图的经验(我仍然用feynmp
它来画……)但这里有一个尝试
\documentclass{article}
\usepackage{tikz}
% \tikz picture vertically centered on math axis
\newcommand*{\ctikz}[2][]{\hbox{\mathsurround=3pt$\vcenter{\hbox{\tikz[#1]{#2}}}$}}
\usetikzlibrary{arrows.meta}
\newcommand*{\I}{\mathrm{i}}
\begin{document}
\[
Z[j] =
\frac{\displaystyle \biggl[ 1 - \frac{\I\,g}{4!} \int
\biggl(
-3 \ctikz{ \draw(0,0)circle(0.2); \draw(0.4,0)circle(0.2); }
+ 6\I
\ctikz{
\draw[{Rays[]}-{Rays[]}](0,0)--(0.8,0);
\draw(0.4,0.2)circle(0.2);}
+ \ctikz{
\draw[{Rays[]}-{Rays[]}](0.3,0.3)--(-0.3,-0.3);
\draw[{Rays[]}-{Rays[]}](-0.3,0.3)--(0.3,-0.3);}
\biggr)
\exp\biggl(-\frac{\I}{2} \int J \Delta_{\mathrm{F}} J \biggr)\biggr] \mathrm{d}z}% end of numerator
{\displaystyle 1 - \frac{\I\,g}{4!} \int \Bigl(-3 \ctikz{\draw(0,0)circle(0.2);\draw(0.4,0)circle(0.2);}\Bigr) \mathrm{d}z}
\]
\end{document}