Aligning pictures inside equation

Question

Consider the following code:

\documentclass{article}
\usepackage{amsmath} % math
\usepackage{amssymb} % math
\usepackage{amsthm}
\usepackage{graphicx} % to use \includegraphics{}
\usepackage{tikz}
\usepackage{tikz-feynman}
\begin{document}
%propagator line
\begin{equation}
\begin{tikzpicture}[baseline=(current  bounding  box.center)]
\begin{feynman}
    \vertex (a);
    \vertex[right= of a] (b);
    \diagram{
    (a) --[fermion, edge label=${k, i\omega_n}$] (b)
};
\end{feynman}
\end{tikzpicture}=\frac{1}{i\omega_n -\epsilon_k}, \quad \begin{tikzpicture}[baseline=(current  bounding  box.center)]
\begin{feynman}
\vertex (a);
\vertex[right= of a] (b);
\diagram{
    (a) --[charged scalar, edge label=${i\omega_n}$] (b)
};
\end{feynman}
\end{tikzpicture}=\frac{1}{i\omega_n -\lambda}.
\end{equation}
\end{document}

whose output is like

I want to align the lines such that it is at the middle of the = sign. How can I do this?

did the answer meet your requirement – js bibra Jul 08 '20 at 09:13 — js bibra, Jul 08 '20 at 09:13

score 6 · Accepted Answer · answered Jul 08 '20 at 10:39

You can use what's suggested in https://tex.stackexchange.com/a/59660/4427, namely

baseline=-\the\fontdimen22\textfont2

Code:

\documentclass{article}
\usepackage{amsmath} % math
\usepackage{amssymb} % math
\usepackage{amsthm}
\usepackage{graphicx} % to use \includegraphics{}
\usepackage{tikz}
\usepackage{tikz-feynman}
\begin{document}
%propagator line
\begin{equation}
\begin{tikzpicture}[baseline=-\the\fontdimen22\textfont2)]
\begin{feynman}
    \vertex (a);
    \vertex[right= of a] (b);
    \diagram{
    (a) --[fermion, edge label=${k, i\omega_n}$] (b)
};
\end{feynman}
\end{tikzpicture}=\frac{1}{i\omega_n -\epsilon_k}, \quad
\begin{tikzpicture}[baseline=-\the\fontdimen22\textfont2]
\begin{feynman}
\vertex (a);
\vertex[right= of a] (b);
\diagram{
    (a) --[charged scalar, edge label=${i\omega_n}$] (b)
};
\end{feynman}
\end{tikzpicture}=\frac{1}{i\omega_n -\lambda}.
\end{equation}
\end{document}

score 4 · Answer 2 · answered Jul 08 '20 at 10:24

Ìt is very simple to obtain with pst-feyn and pst-node:

\documentclass{article}
\usepackage{pst-node, pst-feyn}%,
\usepackage{auto-pst-pdf}
\begin{document}
[ %
\pnode[0,0.6ex]{A}\hspace{3.5em}\pnode[0,0.6ex]{B}\mkern 7mu = \frac{1}{i\omega_n-\epsilon_k},\qquad
\pnode[0,0.6ex]{C}\hspace{3.5em}\pnode[0,0.6ex]{D}\mkern 7mu = \frac{1}{i\omega_n-\lambda}
\psset{linewidth=0.2pt, labelsep=2pt}
\psArrowLine(A)(B)\ncline[linestyle=none]{A}{B}\naput{k, i\omega_n}
\psArrowLinelinestyle=dashed, dash=3pt 2.5pt(D)\ncline[linestyle=none]{C}{D}\naput{ i\omega_n}
]%
\end{document}

score 2 · Answer 3 · answered Jul 08 '20 at 08:58

\documentclass{article}
\usepackage{amsmath} % math
\usepackage{amssymb} % math
\usepackage{amsthm}
\usepackage{graphicx} % to use \includegraphics{}
\usepackage{tikz}
\usepackage{tikz-feynman}
\begin{document}
    %propagator line
    \begin{equation}
    \begin{tikzpicture}[baseline=(current  bounding  box.base)]
    \begin{feynman}
    \vertex (a);
    \vertex[right= of a] (b);
    \diagram{
        (a) --[fermion, edge label=${k, i\omega_n}$] (b)
    };
    \end{feynman}
    \end{tikzpicture}=\frac{1}{i\omega_n -\epsilon_k}, \quad \begin{tikzpicture}[baseline=(current  bounding  box.base)]
    \begin{feynman}
    \vertex (a);
    \vertex[right= of a] (b);
    \diagram{
        (a) --[charged scalar, edge label=${i\omega_n}$] (b)
    };
    \end{feynman}
    \end{tikzpicture}=\frac{1}{i\omega_n -\lambda}.
    \end{equation}
\end{document}

score 1 · Answer 4 · answered Aug 13 '20 at 22:54

I add another short code....using feyn package.

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath,amssymb,feyn}
\begin{document}
\begin{equation}
\feyn{
!{fA}{k,i\omega_{n}}}
=\frac{1}{i\omega_{n} -\epsilon_{k}}, \quad \rlap{$\mkern 16mu\feyn{a}$}\feyn{ !h{i\omega_{n}}}=\frac{1}{i\omega_{n} -\lambda}.
\end{equation}
\end{document}

There are no mistakes, but I think it's normal.

Aligning pictures inside equation

4 Answers4