\documentclass[11pt]{article}
\input{Qcircuit}
\thispagestyle{empty}
\begin{document}
\[
 \Qcircuit @C=.7em @R=.7em {
  \lstick{\ket{0}}    & \gate{H} & \qw & \qw               & \qw               & \qw & \cdots & & \ctrl{4}               & \multigate{3}{\textrm{QFT}_{2n}^{-1}} & \qw  & \meter & \cw \\
  \lstick{\vdots\ \ } & \vdots   &     &                   &                   &     &        & &                        &    \pureghost{\textrm{QFT}_{2n}^{-1}} &      & \vdots &     \\
  \lstick{\ket{0}}    & \gate{H} & \qw & \qw               & \ctrl{2}          & \qw & \cdots & & \qw                    &        \ghost{\textrm{QFT}_{2n}^{-1}} & \qw  & \meter & \cw \\
  \lstick{\ket{0}}    & \gate{H} & \qw & \ctrl{1}          & \qw               & \qw & \cdots & & \qw                    &        \ghost{\textrm{QFT}_{2n}^{-1}} & \qw  & \meter & \cw \\
  \lstick{\ket{1}}    & /^n \qw  & \qw & \gate{U{a^{2^0}}} & \gate{U{a^{2^1}}} & \qw & \cdots & & \gate{U{a^{2^{2n-1}}}} & \qw
 }
\]
\end{document}