\documentclass[11pt]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{physics}

\usepackage{feynmp}
\DeclareGraphicsRule{*}{mps}{*}{}

\begin{document}

\begin{center}
	{\Huge \sc Feynman diagrams}
\end{center}

\begin{fmffile}{freegf}
	\begin{fmfgraph*}(110,60)
		\fmfleft{v1}
		\fmfright{v2}
		\fmflabel{$(\mathbf{r}_1,t_1,s_1)$}{v1}
		\fmflabel{$(\mathbf{r}_2,t_2,s_2)$}{v2}
		\fmf{fermion}{v1,v2}
		\fmfdot{v1}
		\fmfdot{v2}
	\end{fmfgraph*}
\end{fmffile}

\begin{fmffile}{fullgf}
	\begin{fmfgraph*}(110,60)
		\fmfleft{v1}
		\fmfright{v2}
		\fmflabel{$(\mathbf{r}_1,t_1,s_1)$}{v1}
		\fmflabel{$(\mathbf{r}_2,t_2,s_2)$}{v2}
		\fmf{heavy}{v1,v2}
		\fmfdot{v1}
		\fmfdot{v2}
	\end{fmfgraph*}
\end{fmffile}

\begin{fmffile}{perturbation}
	\begin{fmfgraph*}(110,60)
		\fmfleft{i}
		\fmfright{o}
		\fmf{vanilla}{i,m}
		\fmf{vanilla}{m,o}
		\fmfv{decoration.shape=hexagram,label=$(\mathbf{r},t,s)$,label.angle=-90}{m}
		\fmflabel{$(\mathbf{r},t,s)$}{m}
	\end{fmfgraph*}
\end{fmffile}

\begin{fmffile}{interaction}
	\begin{fmfgraph*}(110,60)
		\fmfleft{v1}
		\fmfright{v2}
		\fmflabel{$(\mathbf{r}_1,t_1,s_1)$}{v1}
		\fmflabel{$(\mathbf{r}_2,t_2,s_2)$}{v2}
		\fmf{boson}{v1,v2}
		\fmfdot{v1}
		\fmfdot{v2}
	\end{fmfgraph*}
\end{fmffile}

\begin{fmffile}{conservation}
	\begin{fmfgraph*}(110,60)
		\fmfleft{i1,o1}
		\fmfright{i2,o2}
		\fmf{fermion,label=$\tilde{\mathbf{k}}_1$}{i1,v1}
		\fmf{fermion,label=$\tilde{\mathbf{k}}_2$}{v1,o1}
		\fmf{fermion,label=$\tilde{\mathbf{q}}_1$,label.side=left}{i2,v2}
		\fmf{fermion,label=$\tilde{\mathbf{q}}_2$}{v2,o2}
		\fmf{boson,label=$\mathbf{p}$}{v1,v2}
		\fmfdot{v1}
		\fmfdot{v2}
		\fmfv{label=$\tilde{\mathbf{r}}_1$,label.angle=180}{i1}
		\fmfv{label=$\tilde{\mathbf{r}}_1'$,label.angle=180}{o1}
		\fmflabel{$\tilde{\mathbf{r}}$}{v1}
		\fmflabel{$\tilde{\mathbf{r}}'$}{v2}
		\fmfv{label=$\tilde{\mathbf{r}}_2$,label.angle=0}{i2}
		\fmfv{label=$\tilde{\mathbf{r}}_2'$,label.angle=0}{o2}
	\end{fmfgraph*}
\end{fmffile}

\end{document}