Anonymous 1550
So I am trying to recreate the attached image exactly. But for the upper red ring, I can't seem to have it centered well. I have tried multiple modifications, but it just does not want to center itself like the black dashed ring. Please help.

![Screen Shot 2020-09-06 at 1.52.30 AM.png](/image?hash=2826f8a2c96974d28a9909c370e57001d0c99a0e927298b86fa78cca3459d437)

MWE:


\documentclass[tikz,border=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,calc,positioning,decorations.pathreplacing,calligraphy,bending}
\usepackage{tikzsymbols}
\usepackage{tikz-3dplot}

\begin{document}
\tdplotsetmaincoords{70}{112}
\begin{tikzpicture}[tdplot_main_coords,line cap=round,>=stealth,scale=0.75]
\begin{scope}[rotate=9]
\draw[dashed,thick,canvas is xy plane at z=0] circle[radius=2.75cm];
\end{scope}
\begin{scope}[roll=9]
\draw[dashed,thick,red,canvas is xy plane at z=2] circle[radius=1.75cm];
\end{scope}
\draw[-Latex] (0,0,0) coordinate (O) -- (7,0,0) node[pos=1.2] {$x$};
\draw[-Latex,rotate around={8:(O)}] (O) -- (0,4,0) node[pos=1.1] {$y$};
\draw[-Latex] (O) -- (0,0,4) node[pos=1.1] {$z$};
\end{tikzpicture}
\end{document}

marmot
The depicted diagram does not seem to be an orthographic projection. One can conceivably reproduce it by choosing appropriate basis vectors.

\documentclass[tikz,border=3mm]{standalone}
\usetikzlibrary{arrows.meta,3d}
\begin{document}
\begin{tikzpicture}
\path (-135:0.5) coordinate (ex) (1,0) coordinate (ey) (0,1) coordinate (ez)
(0,0) coordinate (O);
\begin{scope}[x={(ex)},y={(ey)},z={(ez)}]
\begin{scope}[canvas is xy plane at z=0]
\end{scope}
\begin{scope}[canvas is xy plane at z=2,red]
\foreach \X in {0,45,...,315}
{\draw[-Latex]  (O) --(\X:1.75);}
\end{scope}
\begin{scope}[canvas is xy plane at z=-2,blue]
\foreach \X in {0,45,...,315}
{\draw[-Latex]  (O) --(\X:1.75);}
\end{scope}
\draw[dashed,very thin,draw=gray] (0,0,2) node[left] {$\hbar$} edge ++ (0,1.75,0)
(0,0,-2) node[left] {$-\hbar$} edge ++ (0,1.75,0);
\draw[-Latex]  (O) -- (7,0,0) node[pos=1.2] {$x$};
\draw[-Latex] (O) -- (0,4,0) node[pos=1.1] {$y$};
\draw[-Latex] (0,0,-4) -- (0,0,4) node[pos=1.05] {$z$};
\draw[-Latex,thick] (O) -- (0,2.75,0) node[midway,above] {$L$};
\end{scope}
\path (-3,3) node[draw]{$\ell=1$};
\end{tikzpicture}
\end{document}

![Screen Shot 2020-09-07 at 3.31.38 AM.png](/image?hash=e9825b90cb254adb51417b911fc1ee454574a0925c493e33fe879f1816abf3e0)

Notice that I am not claiming that this choice of (ex) yields a perfect reproduction, it is just my first guess. So you may want to play with this basis vector to get a more precise match.

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