我很难将方程中的图表对齐,因为所有内容都位于同一条线上:
如您所见,+ 与外部线不对齐。以下是代码
% !TeX program = xelatex
\documentclass{standalone}
\usepackage[force]{feynmp-auto}
\DeclareGraphicsRule{*}{mps}{*}{} % for being able to read the produced file
\begin{document}
\setlength{\unitlength}{1cm}
\begin{eqnarray}
\begin{fmffile}{psi-phi}
\begin{fmfgraph}(4,3)% units are now in cm
\fmfleft{i}
\fmfright{o}
\fmflabel{$\phi$}{i}
\fmf{fermion}{i,v}
\fmf{dashes}{v,v}
\fmf{fermion}{v,o}
\fmfdot{v}
\end{fmfgraph}
\end{fmffile}
&\quad + \quad&
\begin{fmffile}{phi-psi}
\begin{fmfgraph}(4,3)% units are now in cm
\fmfleft{i}
\fmfright{o}
\fmflabel{$\phi$}{i}
\fmf{dashes}{i,v}
\fmf{fermion}{v,v}
\fmf{dashes}{v,o}
\fmfdot{v}
\end{fmfgraph}
\end{fmffile}
\end{eqnarray}
\end{document}
我正在使用 XelateX 进行编译。另外,我对基于 的解决方案不感兴趣tikz-feynman
。
答案1
为了对齐两个图表,我使用了前后对比\parbox{40mm}
。\parbox{30mm}
结果如下。
\documentclass[12pt,a4paper]{article}
\usepackage[force]{feynmp-auto}
\DeclareGraphicsRule{*}{mps}{*}{} % for being able to read the produced file
\begin{document}
\setlength{\unitlength}{1cm}
\begin{eqnarray}
\begin{fmffile}{psi-phi}
\parbox{40mm}{\begin{fmfgraph}(4,3)% units are now in cm
\fmfleft{i}
\fmfright{o}
\fmflabel{$\phi$}{i}
\fmf{fermion}{i,v}
\fmf{dashes}{v,v}
\fmf{fermion}{v,o}
\fmfdot{v}
\end{fmfgraph}}
\end{fmffile}
&\quad + \quad&
\begin{fmffile}{phi-psi}
\parbox{30mm}{\begin{fmfgraph}(4,3)% units are now in cm
\fmfleft{i}
\fmfright{o}
\fmflabel{$\phi$}{i}
\fmf{dashes}{i,v}
\fmf{fermion}{v,v}
\fmf{dashes}{v,o}
\fmfdot{v}
\end{fmfgraph}}
\end{fmffile}
\end{eqnarray}
\end{document}