gravitons.tex (22 lines)
\documentclass{standalone}
\usepackage{tikz-feynman}
\begin{document}
$\displaystyle\partial_t V_g
= \raisebox{0.5ex}{\feynmandiagram [inline=(a.base)] {
a [dot] -- [charged boson, quarter left, edge label=$p$] b
-- [photon, quarter left] c [dot]
-- [charged boson, quarter left, edge label=$p$] d [crossed dot]
-- [charged boson, quarter left, edge label=$p$] a,
f1 -- [photon] c,
i1 -- [photon] a,
};}
\enskip + \enskip
\raisebox{0.5ex}{\feynmandiagram [inline=(a.base)] {
{i1, i2} -- [photon] a [dot]
-- [charged boson, half left, edge label=$p$] b [crossed dot]
-- [charged boson, half left, edge label=$p$] a,
};}$
\end{document}