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\begin{equation*}\tilde{U}_{\text{QFT}}\left | x \right>:=\bigotimes_{i=0}^{n-1}\left(\left | 0 \right>+e^{i2\pi \sum_{j=0}^{i}x_j2^{j-i-1}}\left | 1 \right>\right)/\sqrt{2}.
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