diff --git a/thesis/chapters/graph_simulator.tex b/thesis/chapters/graph_simulator.tex index 2d2553e..cc6ebcf 100644 --- a/thesis/chapters/graph_simulator.tex +++ b/thesis/chapters/graph_simulator.tex @@ -37,21 +37,21 @@ Where $X = \left(\begin{array}{cc} 0 & 1 \\ 1 & 0\end{array}\right)$, C_n := \{U \in SU(2) | UpU^\dagger \in P_n \forall p \in P_n\} \end{equation} is called the Clifford group on $n$ qbits. - $C_1 =: C_L$ is called the local Clifford group. + $C_1$ is called the local Clifford group. \end{definition} -One can show that the Clifford group $C_n$ can be generated using the elements of $C_L$ acting on all qbits and +One can show that the Clifford group $C_n$ can be generated using the elements of $C_1$ acting on all qbits and the controlled phase gate $CZ$ between all qbits\cite{andersbriegel2005}. It is worth noting that the $CX$ gate can be -generated using $CZ$ and $C_L$ gates. +generated using $CZ$ and $C_1$ gates. \begin{lemma} - Let $a \in C_L$ then $\forall \phi \in [0, 2\pi)$ also $\exp(i\phi)a \in C_L$. + Let $a \in C_1$ then $\forall \phi \in [0, 2\pi)$ also $\exp(i\phi)a \in C_1$. \textbf{Note}: This is also true for $C_n \forall n >= 1$. \end{lemma} \begin{proof} - Let $a' := \exp(i\phi)a$. $a' \in C_L$ iff $a'pa^{\prime\dagger} \in P \forall p \in P$. + Let $a' := \exp(i\phi)a$. $a' \in C_1$ iff $a'pa^{\prime\dagger} \in P \forall p \in P$. \begin{equation} \begin{aligned} @@ -115,16 +115,40 @@ generated using $CZ$ and $C_L$ gates. \end{proof} \begin{corrolary} - One can disregard global phases of elements of the $C_L$ group. + One can disregard global phases of elements of the $C_1$ group. \end{corrolary} \begin{proof} As it has been shown above a quantum computer cannot measure global phases. Also the entanglement gates $CX, CZ$ map qbit-global phases to multi-qbit-global phases which cannot - be measured. It has been shown above that one can choose the $C_L$ operators such that they do not yield + be measured. It has been shown above that one can choose the $C_1$ operators such that they do not yield a phase. \end{proof} +\begin{definition} + \begin{equation} + C_L := \{a \in C_1 | \nexists \phi \in [0, 2\pi), b \in C_L : a = \exp(i\phi)b\} + \end{equation} + Is called the non-trivial local Clifford group. +\end{definition} + +\textbf{Remark.} When computing the elements of $C_L$ and their products one will realize that $C_L$ is not a group. +If one however disregards a global phase the product of two $C_L$ elements will be in $C_L$ again. Because the global phases +can be disregarded as discussed above $C_L$ will be used from now on instead of $C_1$. + +\begin{theorem} + \begin{equation} + | C_L | = 24 + \end{equation} +\end{theorem} + +\begin{proof} + It is clear that $\forall a \in C_L$ a is a group isomorphism $P \circlearrowleft$: $apa^\dagger a p' a^\dagger = a pp'a^\dagger$. + Therefore $a$ will preserve the (anti-)commutator relations of $P$. Also $P$ is generated by $X,Z$ when disregarding a phase wich + does not matter for anticommutator relations. + This means that $X$ can be mapped to any $p \in P$ which are six elements disregarding +\end{proof} + \subsection{Graph Storage} diff --git a/thesis/main.tex b/thesis/main.tex index c2fe5c4..74aea51 100644 --- a/thesis/main.tex +++ b/thesis/main.tex @@ -17,6 +17,7 @@ \newtheorem{postulate}{Postulate} \newtheorem{corrolary}{Corrolary} \newtheorem{lemma}{Lemma} +\newtheorem{theorem}{Theorem} \numberwithin{equation}{section} @@ -48,6 +49,12 @@ Simulator with a Focus on Simulation in the Graph Formalism } \include{chapters/graph_simulator} +\section{Appendix} + +\subsection{Computing the Local Clifford Group and the Products of its Elements} + +%\include{chapters/C_L_elements_and_products} + %\backmatter \bibliographystyle{unsrt}