And that is a fraction:
\begin{gather} \Psi = \frac{a}{b} \end{gather}
\begin{eqnarray}
\begin{aligned}
%\left|\alpha\upsilon j;m_{\mathrm{exp}}=0\right\rangle & =0.7071\left|\alpha\upsilon j;m=+1\right\rangle
% & -0.7071\left|\alpha\upsilon j;m=-1\right\rangle,
\left|\alpha\upsilon j;m_{\mathrm{exp}}=0\right\rangle & =\frac{1}{\sqrt{2}}\left(\left|\alpha\upsilon j;m=+1\right\rangle\right.
& -\left.\left|\alpha\upsilon j;m=-1\right\rangle\right),
\end{aligned}
\end{eqnarray}