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\subfile{sections/results}
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% Conclusion
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% \subfile{sections/conclusion}
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\subfile{sections/conclusion}
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% Notes
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% \subfile{draft}
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@@ -3,7 +3,8 @@
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\begin{document}
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\appendix
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\section{The Crank-Nicholson method}\label{ap:crank_nicolson}
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The Crank-Nicolson (CN) approach consider both the forward difference, an explicit scheme,
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The Crank-Nicolson (CN) approach consider both the forward difference, an explicit
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scheme,
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\begin{equation*}
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\frac{u_{\ivec, \jvec}^{n+1} - u_{\ivec, \jvec}^{n}}{\Delta t} = F_{\ivec, \jvec}^{n} \ ,
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\end{equation*}
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@@ -20,9 +21,11 @@ The parameter $\theta$ is introduced for a general approach, however, for CN $\t
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\frac{u_{\ivec, \jvec}^{n+1} - u_{\ivec, \jvec}^{n}}{\Delta t} &= \frac{1}{2} \bigg[ F_{\ivec, \jvec}^{n+1} + F_{\ivec, \jvec}^{n} \bigg] \\
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\end{align*}
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We need the first derivative in respect to both time and position, as well as the second derivative in respect to position. Taylor expanding will result in a discretized version, assume this is known...
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We need the first derivative in respect to both time and position, as well as the
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second derivative in respect to position. Taylor expanding will result in a discretized
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version.
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Schrödinger contain $i$ at the lhs, factor it as
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The Schrödinger equation contains $i$ on the left hand side, we rewrite it as
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\begin{align*}
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\frac{u_{\ivec, \jvec}^{n+1} - u_{\ivec, \jvec}^{n}}{\Delta t} &= \frac{1}{2i} \bigg[ F_{\ivec, \jvec}^{n+1} + F_{\ivec, \jvec}^{n} \bigg] \\
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&= -\frac{i}{2} \bigg[ F_{\ivec, \jvec}^{n+1} + F_{\ivec, \jvec}^{n} \bigg] \ ,
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@@ -44,8 +47,7 @@ the left hand side, and the terms containing $n$ time step on the right hand sid
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&= u_{\ivec, \jvec}^{n} + \frac{i \Delta t}{2 \Delta x^{2}} \big[ u_{\ivec+1, \jvec}^{n} - 2u_{\ivec, \jvec}^{n} + u_{\ivec-1, \jvec}^{n} \big] \\
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& \quad + \frac{i \Delta t}{2 \Delta y^{2}} \big[ u_{\ivec, \jvec+1}^{n} - 2u_{\ivec, \jvec}^{n} + u_{\ivec, \jvec-1}^{n} \big] - \frac{i \Delta t}{2} v_{\ivec, \jvec} u_{\ivec, \jvec}^{n}
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\end{align*}
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In addition, since we will use an equal step size $h$ in both $x$ and $y$ direction,
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we can use
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Since we will use an equal step size $h$ in both $x$ and $y$ direction, we can use
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\begin{align*}
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\frac{i \Delta t}{2 \Delta h^{2}} = \frac{i \Delta t}{2 \Delta x^{2}} = \frac{i \Delta t}{2 \Delta y^{2}} \ ,
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\end{align*}
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@@ -53,7 +55,7 @@ and define
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\begin{align*}
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r \equiv \frac{i \Delta t}{2 \Delta h^{2}}
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\end{align*}
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Now, the discretized Schrödinger equation can be written as
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Now, the discretized Schrödinger equation can be rewritten as
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\begin{align*}
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& u_{\ivec, \jvec}^{n+1} - r \big[ u_{\ivec+1, \jvec}^{n+1} - 2u_{\ivec, \jvec}^{n+1} + u_{\ivec-1, \jvec}^{n+1} \big] \\
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& - r \big[ u_{\ivec, \jvec+1}^{n+1} - 2u_{\ivec, \jvec}^{n+1} + u_{\ivec, \jvec-1}^{n+1} \big] + \frac{i \Delta t}{2} v_{\ivec, \jvec} u_{\ivec, \jvec}^{n+1} \\
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@@ -97,6 +99,8 @@ $(M-2)^{2} \times (M-2)^{2} = 9 \times 9$ given by
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\section{Figures}\label{ap:figures}
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We created colormap plots of the real and imaginary part of $u_{\ivec, \jvec}$,
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in Figure \ref{fig:colormap_real_imag}.
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\begin{figure*}
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\centering
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\begin{subfigure}[b]{0.3\textwidth}
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@@ -119,9 +123,7 @@ $(M-2)^{2} \times (M-2)^{2} = 9 \times 9$ given by
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\caption{Re$(u_{\ivec, \jvec})$ at time $t=0.002$.}
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\label{fig:colormap_2_real}
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\end{subfigure}
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\newline
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\begin{subfigure}[b]{0.3\textwidth}
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\centering
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\includegraphics[width=\textwidth]{images/color_map_0_imag.pdf}
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@@ -142,7 +144,17 @@ $(M-2)^{2} \times (M-2)^{2} = 9 \times 9$ given by
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\caption{Im$(u_{\ivec, \jvec})$ at time $t=0.002$.}
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\label{fig:colormap_2_imag}
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\end{subfigure}
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\caption{The time evolution of the probability function $p_{\ivec, \jvec}^{n}$.}
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\label{fig:colormap}
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\caption{The time evolution of Re($u_{\ivec, \jvec}$) and Im($u_{\ivec, \jvec}$),
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for time steps $t=[0, 0.001, 0.002]$.}
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\label{fig:colormap_real_imag}
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\end{figure*}
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% \begin{figure*}
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% \centering
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% \includegraphics[width=0.9\textwidth]{images/color_map_all.pdf}
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% \caption{The time evolution of the probability function $p_{\ivec, \jvec}^{n}$ (top row),
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% Re($u_{\ivec, \jvec}^{n}$) (middle row), and Im($u_{\ivec, \jvec}^{n}$) (bottom row).
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% Time step $t=0$ in the left column, $t=0.001$ in the middle column, and $t=0.002$
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% in the right column.}
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% \label{fig:colormap_all}
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% \end{figure*}
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\end{document}
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@@ -273,8 +273,8 @@ and for the simulations, we used the parameter settings in Table \ref{tab:sim_se
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To check if the total probability is conserved over time, and that the implementation
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was correct, we computed the deviation from $1.0$ given by
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\begin{align*}
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s^{n} &= |\sum_{\ivec , \jvec} p_{\ivec , \jvec}^{n} - 1| \\
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&= |\sum_{\ivec , \jvec} u_{\ivec , \jvec}^{n*} u_{\ivec , \jvec}^{n} - 1| \ .
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s^{n} &= |1.0 - \sum_{\ivec , \jvec} p_{\ivec , \jvec}^{n}| \\
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&= |1.0 - \sum_{\ivec , \jvec} u_{\ivec , \jvec}^{n*} u_{\ivec , \jvec}^{n}| \ .
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\end{align*}
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\subsection{Tools}\label{ssec:tools} %
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@@ -74,6 +74,20 @@ areas at both sides of the barries. Some of the probability function is reflecte
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by the barrier, while the the rest spread out after passing the barrier. This is
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a consequence of the wave-particle duality.
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To compare the probability function $p_{\ivec, \jvec}$ for all the time steps in
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a colormap plot, with the real and imaginary part of $u_{\ivec, \jvec}$, we created
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Figure \ref{fig:colormap_all}. Where we excluded all x- and y-ticks, and labels, to
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better visualize the diffraction pattern.
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\begin{figure}
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\centering
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\includegraphics[width=\linewidth]{images/color_map_all.pdf}
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\caption{The time evolution of the probability function $p_{\ivec, \jvec}^{n}$ (top row),
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Re($u_{\ivec, \jvec}$) (middle row), and Im($u_{\ivec, \jvec}$) (bottom row).
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Time step $t=0$ in the left column, $t=0.001$ in the middle column, and $t=0.002$
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in the right column.}
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\label{fig:colormap_all}
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\end{figure}
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\subsection{Particle detection}\label{ssec:particle_detection}
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% Problem 9: Plot detection probability for single-, double- and triple-slit
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