- #1
Peter_Newman
- 155
- 11
Hello,
I am currently working on this task here. Given is a Toffoli gate. Now it is stated that there is an equivalent quantum circuit. I tried to show the equivalence, for example by looking at case ##|111\rangle##.
However, with what I have calculated so far, I do not come to the conclusion that the circuits are equivalent.
I have rewritten the term V first:
$$V=(1-i)\frac{I+iX}{2}=\begin{pmatrix}0.5-0.5i&0.5+0.5i\\0.5+0.5i&0.5-0.5i\end{pmatrix}$$
Now I just start with the case ##|111\rangle##. This should, because it comes to the equivalence dof the Toffoli gate at the end of ##|110\rangle## come out.
$$|111\rangle\xrightarrow{V} |11\rangle\begin{pmatrix}0.5-0.5i&0.5+0.5i\\0.5+0.5i&0.5-0.5i\end{pmatrix}\begin{pmatrix}0\\1\end{pmatrix}=|11\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}\xrightarrow{CNOT}|10\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}$$
$$\left(V^T\right)^{*}=\begin{pmatrix}0.5+0.5i&0.5-0.5i\\0.5-0.5i&0.5+0.5i\end{pmatrix}$$
$$|10\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}\xrightarrow{\left(V^T\right)^{*}} |10\rangle\begin{pmatrix}0.5+0.5i&0.5-0.5i\\0.5-0.5i&0.5+0.5i\end{pmatrix}\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}=|10\rangle|1\rangle$$
$$|10\rangle|1\rangle\xrightarrow{CNOT} |11\rangle|1\rangle\xrightarrow{V}|11\rangle\begin{pmatrix}0.5-0.5i&0.5+0.5i\\0.5+0.5i&0.5-0.5i\end{pmatrix}\begin{pmatrix}0\\1\end{pmatrix}=|11\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}\neq |110\rangle$$
It could be that I made a mistake in my calculation. What do you all mean?
I am currently working on this task here. Given is a Toffoli gate. Now it is stated that there is an equivalent quantum circuit. I tried to show the equivalence, for example by looking at case ##|111\rangle##.
However, with what I have calculated so far, I do not come to the conclusion that the circuits are equivalent.
I have rewritten the term V first:
$$V=(1-i)\frac{I+iX}{2}=\begin{pmatrix}0.5-0.5i&0.5+0.5i\\0.5+0.5i&0.5-0.5i\end{pmatrix}$$
Now I just start with the case ##|111\rangle##. This should, because it comes to the equivalence dof the Toffoli gate at the end of ##|110\rangle## come out.
$$|111\rangle\xrightarrow{V} |11\rangle\begin{pmatrix}0.5-0.5i&0.5+0.5i\\0.5+0.5i&0.5-0.5i\end{pmatrix}\begin{pmatrix}0\\1\end{pmatrix}=|11\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}\xrightarrow{CNOT}|10\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}$$
$$\left(V^T\right)^{*}=\begin{pmatrix}0.5+0.5i&0.5-0.5i\\0.5-0.5i&0.5+0.5i\end{pmatrix}$$
$$|10\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}\xrightarrow{\left(V^T\right)^{*}} |10\rangle\begin{pmatrix}0.5+0.5i&0.5-0.5i\\0.5-0.5i&0.5+0.5i\end{pmatrix}\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}=|10\rangle|1\rangle$$
$$|10\rangle|1\rangle\xrightarrow{CNOT} |11\rangle|1\rangle\xrightarrow{V}|11\rangle\begin{pmatrix}0.5-0.5i&0.5+0.5i\\0.5+0.5i&0.5-0.5i\end{pmatrix}\begin{pmatrix}0\\1\end{pmatrix}=|11\rangle\begin{pmatrix}0.5+0.5i\\0.5-0.5i\end{pmatrix}\neq |110\rangle$$
It could be that I made a mistake in my calculation. What do you all mean?