\documentclass[preview,convert={indir={aux/}, outdir={aux/}, outputdir={aux/}},border=40px]{standalone}
\usepackage{quantumcubemodel}

\begin{document}
\begin{qcmx}
    \node at (5, 5, 0) {\Huge \textbf{Darstellung eines Qubits}};
    \node at (5, 3, 0) {\Large Im Zustand $\ket{\varphi} = \sqrt{\frac{3}{4}} \ket{0} + \sqrt{\frac{1}{4}} \ket{1}$};
    \qcmxO{0.86}
    \qcmxI{0.5}
    \qcmxRenderQ
\end{qcmx}
\end{document}