Fix expectation values

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Janita Willumsen 2023-12-05 19:17:54 +01:00
parent e4baf0bbca
commit b99abbc291
4 changed files with 14 additions and 14 deletions

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@ -8,10 +8,10 @@
Carlo sampling method. We determined the time of equilibrium to be approximately Carlo sampling method. We determined the time of equilibrium to be approximately
$5000$ Monte Carlo cycles, and used the following samples to find the probability $5000$ Monte Carlo cycles, and used the following samples to find the probability
distribution at temperature $T_{1} = 1.0 J / k_{B}$, and $T_{2} = 2.4 J / k_{B}$. distribution at temperature $T_{1} = 1.0 J / k_{B}$, and $T_{2} = 2.4 J / k_{B}$.
For $T_{1}$ the mean energy per spin is $\langle \epsilon \rangle \approx -1.9969 J$, For $T_{1}$ the mean energy per spin is $\langle \epsilon \rangle \approx -1.9972 J$,
with a variance $\text{Var} (\epsilon) = 0.0001$. And for $T_{2}$, close to the critical with a variance $\text{Var} (\epsilon) = 0.0001$. And for $T_{2}$, close to the critical
temperature, the mean energy per spin is $\langle \epsilon \rangle \approx -1.2370 J$, temperature, the mean energy per spin is $\langle \epsilon \rangle \approx -1.2367 J$,
with a variance $\text{Var} (\epsilon) = 0.0203$. In addition, we estimated with a variance $\text{Var} (\epsilon) = 0.0202$. In addition, we estimated
the expected energy and magnetization per spin, the heat capacity and magnetic the expected energy and magnetization per spin, the heat capacity and magnetic
susceptibility. We have estimated the critical temperatures of finite lattice sizes, susceptibility. We have estimated the critical temperatures of finite lattice sizes,
and used these values to approximate the critical temperature of a lattice of and used these values to approximate the critical temperature of a lattice of

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@ -216,7 +216,7 @@ the magnetic susceptibility.
\label{fig:phase_susceptibility_1M} \label{fig:phase_susceptibility_1M}
\end{figure} \end{figure}
Result of profiling using Score-P in Figure \ref{fig:scorep_assessment}. Assessment of profiling using Score-P in Figure \ref{fig:scorep_assessment}.
\begin{figure}[H] \begin{figure}[H]
\centering \centering
\includegraphics[width=\linewidth]{../images/profiling.pdf} \includegraphics[width=\linewidth]{../images/profiling.pdf}

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@ -21,9 +21,9 @@ Continuing, we used the generated samples to compute energy per spin $\langle \e
magnetization per spin $\langle |m| \rangle$, heat capacity $C_{V}$, and $\chi$. magnetization per spin $\langle |m| \rangle$, heat capacity $C_{V}$, and $\chi$.
In addition, we estimated the probability distribution for temperatures $T_{1} = 1.0 J / k_{B}$, In addition, we estimated the probability distribution for temperatures $T_{1} = 1.0 J / k_{B}$,
and $T_{2} = 2.4 J / k_{B}$. We found that for $T_{1}$ the expected mean energy and $T_{2} = 2.4 J / k_{B}$. We found that for $T_{1}$ the expected mean energy
per spin is $\langle \epsilon \rangle \approx -1.9969 J$, with a variance $\text{Var} (\epsilon) = 0.0001$. per spin is $\langle \epsilon \rangle \approx -1.9972 J$, with a variance $\text{Var} (\epsilon) = 0.0001$.
And for $T_{2}$, the mean energy per spin is $\langle \epsilon \rangle \approx -1.2370 J$, And for $T_{2}$, the mean energy per spin is $\langle \epsilon \rangle \approx -1.2367 J$,
with a variance $\text{Var} (\epsilon) = 0.0203$. with a variance $\text{Var} (\epsilon) = 0.0202$.
We estimated the expected energy and magnetization per spin, in addition to the We estimated the expected energy and magnetization per spin, in addition to the
heat capacity and susceptibility for lattices of size $L = {20, 40, 60, 80, 100}$. heat capacity and susceptibility for lattices of size $L = {20, 40, 60, 80, 100}$.

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@ -26,16 +26,16 @@ The lattice was initialized in an ordered and an unordered state, for both tempe
no change in expectation value of energy or magnetization for $T_{1}$, when we no change in expectation value of energy or magnetization for $T_{1}$, when we
initialized the lattice in an ordered state. As for the unordered initialized initialized the lattice in an ordered state. As for the unordered initialized
lattice, we first observed a change in expectation values, and a stabilization around lattice, we first observed a change in expectation values, and a stabilization around
$5000$ Monte Carlo cycles. The expected energy per spin is $\langle \epsilon \rangle = -2$ $5000$ Monte Carlo cycles. The expected energy per spin is $\langle \epsilon \rangle \approx -2$
and the expected magnetization per spin is $\langle |m| \rangle = 1.0$. % add something about what is expected for $T_{1}$ ? and the expected magnetization per spin is $\langle |m| \rangle \approx 1$. % add something about what is expected for $T_{1}$ ?
For $T_{2}$ we observed a change in expectation values for both the ordered and the For $T_{2}$ we observed a change in expectation values for both the ordered and the
unordered lattice. unordered lattice.
% \begin{align*} % \begin{align*}
% p(s|T=1.0) &= \frac{1}{e^{-\beta \sum E(s)}} e^{-\beta E(s)} \\ % p(s|T=1.0) &= \frac{1}{e^{-\beta \sum E(s)}} e^{-\beta E(s)} \\
% &= \frac{1}{e^{-(1/k_{B}) \sum E(s)}} e^{-(1/k_{B}) E(s)} \ . % &= \frac{1}{e^{-(1/k_{B}) \sum E(s)}} e^{-(1/k_{B}) E(s)} \ .
% \end{align*} % \end{align*}
For $T_{2}$ we observe an increase in expected energy per spin $\langle \epsilon \rangle \approx -1.23$, For $T_{2}$ we observe an increase in expected energy per spin $\langle \epsilon \rangle \approx -1.25$,
and a decrease in expected magnetization per spin $\langle |m| \rangle \approx 0.46$. and a decrease in expected magnetization per spin $\langle |m| \rangle \approx 0.47$.
% Burn-in figures % Burn-in figures
\begin{figure}[H] \begin{figure}[H]
\centering \centering
@ -69,7 +69,7 @@ We used the estimated burn-in time of $5000$ Monte Carlo cycles as starting time
samples. To visualize the distribution of energy per spin $\epsilon$, we used histograms samples. To visualize the distribution of energy per spin $\epsilon$, we used histograms
with a bin size $0.02$. In Figure \ref{fig:histogram_1_0} we show the distribution with a bin size $0.02$. In Figure \ref{fig:histogram_1_0} we show the distribution
for $T_{1}$. Where the resulting expectation for $T_{1}$. Where the resulting expectation
value of energy per spin is $\langle \epsilon \rangle = -1.9969$, with a low variance value of energy per spin is $\langle \epsilon \rangle = -1.9972$, with a low variance
of Var$(\epsilon) = 0.0001$. % of Var$(\epsilon) = 0.0001$. %
\begin{figure}[H] \begin{figure}[H]
\centering \centering
@ -78,14 +78,14 @@ of Var$(\epsilon) = 0.0001$. %
\label{fig:histogram_1_0} \label{fig:histogram_1_0}
\end{figure} % \end{figure} %
In Figure \ref{fig:histogram_2_4}, for $T_{2}$, the samples of energy per spin is In Figure \ref{fig:histogram_2_4}, for $T_{2}$, the samples of energy per spin is
centered around the expectation value $\langle \epsilon \rangle = -1.2370$. % centered around the expectation value $\langle \epsilon \rangle = -1.2367$. %
\begin{figure}[H] \begin{figure}[H]
\centering \centering
\includegraphics[width=\linewidth]{../images/pd_estimate_2_4.pdf} \includegraphics[width=\linewidth]{../images/pd_estimate_2_4.pdf}
\caption{Distribution of values of energy per spin, when temperature is $T = 2.4 J / k_{B}$} \caption{Distribution of values of energy per spin, when temperature is $T = 2.4 J / k_{B}$}
\label{fig:histogram_2_4} \label{fig:histogram_2_4}
\end{figure} % \end{figure} %
However, we observed a higher variance of Var$(\epsilon) = 0.0203$. When the temperature However, we observed a higher variance of Var$(\epsilon) = 0.0202$. When the temperature
increased, the system moved from an ordered to an unordered state. The change in increased, the system moved from an ordered to an unordered state. The change in
system state, or phase transition, indicates the temperature is close to a critical system state, or phase transition, indicates the temperature is close to a critical
point. point.