I have prepared the following
\begin{equation}
\Qcircuit @C=1em @R=.7em {
& \gate{H} & \ctrl{1} & \gate{H} & \qw \\
& \gate{H} & \targ & \gate{H} & \qw }= \Qcircuit @C=1em @R=.7em {
& \targ & \qw \\
& \ctrl{-1} & \qw
}
\end{equation}
which outputs the correct circuit. However, the equals sign is aligned with the top wire in the circuit. I'd like to align the equals sign in the middle of the circuits to improve the aesthetics. Could someone show how this is implemented?
For clarity I include a picture of the output, so that the current alignment can be visualized


$$is deprecated in LaTeX, see Why is\[ … \]preferable to$$? – egreg May 15 '16 at 10:07