\documentclass[preview, border=40px]{standalone}
\usepackage{../quantumcubemodel}
\begin{document}
\textbf{Two qubits in a state with arbitrary amplitudes and phases}
\begin{qcmx}
    \qcmxOO[30]{0.5}
    \qcmxOI{0.71}
%   \qcmxIO{0} % can be left out, since this is the default value
    \qcmxII[145]{0.5}
    \qcmxRenderQQ
\end{qcmx}
\end{document}