修改我的费曼图:绘制正方形和从正方形中引出的线条
我有以下代码: \documentclass[border=3mm]{standalone} \usepackage{tikz-feynman} \usetikzlibrary{shapes.geometric} \usepackage{amsmath} \begin{tikzpicture} \begin{feynman} \node[shape=circle,draw=black, inner sep=0pt,minimum size=20pt] (m) at ( 0, 0) {}; \node[shape=rectangle,fill=black] ...