Edit and compile if you like:
\documentclass[tikz]{standalone}\usetikzlibrary{patterns}\tikzset{cross/.style={path picture={\draw[black] (path picture bounding box.south east) -- (path picture bounding box.north west) (path picture bounding box.south west) -- (path picture bounding box.north east);}}}\def\unit{0.7}\begin{document}% Diagram 1\begin{tikzpicture}\draw[thick] (0,0) circle (\unit);\draw (-2*\unit,0) -- (-\unit,0) (\unit,0) -- (2*\unit,0);\draw[fill=white,cross] (0,\unit) circle (0.15*\unit) node[below=2*\unit] {$\partial_k R_k$};\draw[fill=white,postaction={pattern=north east lines}] (\unit,0) circle (0.2*\unit) node[above right] {$\Gamma_k^{(3)}$} (-\unit,0) circle (0.2*\unit) node[above left] {$\Gamma_k^{(3)}$};\end{tikzpicture}% Diagram 2\begin{tikzpicture}\draw[thick] (0,0) circle (\unit);\draw (-2*\unit,0) -- (-\unit,0) (\unit,0) -- (2*\unit,0);\draw[fill=white,cross] (0,-\unit) circle (0.15*\unit) node[above=2*\unit] {$\partial_k R_k$};\draw[fill=white,postaction={pattern=north east lines}] (\unit,0) circle (0.2*\unit) node[above right] {$\Gamma_k^{(3)}$} (-\unit,0) circle (0.2*\unit) node[above left] {$\Gamma_k^{(3)}$};\end{tikzpicture}% Diagram 3\begin{tikzpicture}\draw[thick] (0,0) circle (\unit);\draw (-2*\unit,-\unit) -- (2*\unit,-\unit);\draw[fill=white,cross] (0,\unit) circle (0.15*\unit) node[below=2*\unit] {$\partial_k R_k$};\draw[fill=white,postaction={pattern=north east lines}] (0,-\unit) circle (0.2*\unit) node[above=3*\unit] {$\Gamma_k^{(4)}$};
Click to download: propagator-fluctuations.tex
Open in Overleaf: propagator-fluctuations.tex
This file is available on tikz.netlify.app and on GitHub and is MIT licensed.
See more on the author page of Janosh Riebesell..