1
Fork 0

Remove matroid thingy

This commit is contained in:
prescientmoon 2025-03-20 17:06:00 +01:00
parent 966f244e47
commit 325d12ba7e
Signed by: prescientmoon
SSH key fingerprint: SHA256:UUF9JT2s8Xfyv76b8ZuVL7XrmimH4o49p4b+iexbVH4

View file

@ -75,16 +75,7 @@ code-for-last-col = \color{blue}
\end{enumerate} \end{enumerate}
\end{frame} \end{frame}
% should we make is so that these bullet points appear one after another? Yes
\begin{frame}{Abstracting Independence - Motivation}
\begin{itemize}
\item 1
\item 2
\end{itemize}
\end{frame}
\include{prerequisites} \include{prerequisites}
\include{isospectral} \include{isospectral}
\begin{frame}[fragile]{CMB Anisotropy of Homogeneous Spherical Spaces} \begin{frame}[fragile]{CMB Anisotropy of Homogeneous Spherical Spaces}
@ -92,9 +83,9 @@ code-for-last-col = \color{blue}
\item Manifolds $\textcolor{blue}{M} := \mathbb{S}^3 /_ \sim$ where $\sim $ identifies the orbits of finite $H \leq SO(4)$ \item Manifolds $\textcolor{blue}{M} := \mathbb{S}^3 /_ \sim$ where $\sim $ identifies the orbits of finite $H \leq SO(4)$
\item Helmholtz equation on $\textcolor{blue}{M}$ given by \item Helmholtz equation on $\textcolor{blue}{M}$ given by
\begin{align*} \begin{align*}
(\Delta + E_{\textcolor{red}{\beta}}^{\textcolor{blue}{M}})\psi_{\textcolor{red}{\beta}}^{{\textcolor{blue}{M}}, i} = 0 (\Delta + E_{\textcolor{red}{\beta}}^{\textcolor{blue}{M}})\psi_{\textcolor{red}{\beta}}^{{\textcolor{blue}{M}}, i} = 0
\end{align*} \end{align*}
\item In fact $E_{\textcolor{red}{\beta}}^m = {\textcolor{red}{\beta}}^2-1$ for $\textcolor{red}{\beta} \in \mathbb{N}$ we call $\textcolor{red}{\beta}$ a wave number \item In fact $E_{\textcolor{red}{\beta}}^m = {\textcolor{red}{\beta}}^2-1$ for $\textcolor{red}{\beta} \in \mathbb{N}$ we call $\textcolor{red}{\beta}$ a wave number
@ -138,15 +129,15 @@ code-for-last-col = \color{blue}
\begin{frame}{CMB radiation in an inhomogeneous spherical space} \begin{frame}{CMB radiation in an inhomogeneous spherical space}
\begin{itemize} \begin{itemize}
\item Manifolds of the form $\mathbb S/\Gamma$ with $\Gamma$ a group acting on $\mathbb S^3$. \item Manifolds of the form $\mathbb S/\Gamma$ with $\Gamma$ a group acting on $\mathbb S^3$.
\item Multi-connected space: it has non-contractable loops \item Multi-connected space: it has non-contractable loops
\item Inhomogeneous space: it does not look identical from every point in space \item Inhomogeneous space: it does not look identical from every point in space
\item Fixing $|\Gamma|=8$, we have three multi-connected manifolds, up to equivalence: \item Fixing $|\Gamma|=8$, we have three multi-connected manifolds, up to equivalence:
\begin{enumerate} \begin{enumerate}
\item homogeneous: $N3$ and $L(8,1)$ \item homogeneous: $N3$ and $L(8,1)$
\item inhomogeneous: $N2 \equiv L(8,3)$ \item inhomogeneous: $N2 \equiv L(8,3)$
\end{enumerate} \end{enumerate}
\item Results: inhomogeneous spaces have more variety in CMB anisotropies than homogeneous spaces, because observer dependency changes the suppression of CMB anisotropies. \item Results: inhomogeneous spaces have more variety in CMB anisotropies than homogeneous spaces, because observer dependency changes the suppression of CMB anisotropies.
\end{itemize} \end{itemize}
@ -155,34 +146,34 @@ code-for-last-col = \color{blue}
\section{Test for anisotropy in the mean of the CMB temperature fluctuation in spherical harmonic space} \section{Test for anisotropy in the mean of the CMB temperature fluctuation in spherical harmonic space}
\begin{frame}{The setup} \begin{frame}{The setup}
From the perspective of an Earth-based observer, we can view CMB as a function defined on the celestial sphere $\mathbb{S}^2$. \\ From the perspective of an Earth-based observer, we can view CMB as a function defined on the celestial sphere $\mathbb{S}^2$. \\
So, $\Delta T(\hat{n})$ expanded using \textit{spherical harmonics}, with $a_{\ell m}$ its coefficients.\\ So, $\Delta T(\hat{n})$ expanded using \textit{spherical harmonics}, with $a_{\ell m}$ its coefficients.\\
We assume the fluctuations: We assume the fluctuations:
\begin{itemize} \begin{itemize}
\item Statistically isotropic and homogeneous in the mean. \item Statistically isotropic and homogeneous in the mean.
\item Gaussian distribution. \item Gaussian distribution.
\item $\textcolor{blue}{a_{\ell m}}$ are independent Gaussian variables. \item $\textcolor{blue}{a_{\ell m}}$ are independent Gaussian variables.
\end{itemize} \end{itemize}
Coefficients should satisfy:$\langle \textcolor{blue}{a_{\ell m}} \rangle = 0$ \\ Coefficients should satisfy:$\langle \textcolor{blue}{a_{\ell m}} \rangle = 0$ \\
\textbf{\textcolor{red}{Remark:}} $\langle \textcolor{blue}{a_{\ell m}} \rangle \neq 0$, \textbf{suggests possible anisotropies or preferred directions in the universe} \textbf{\textcolor{red}{Remark:}} $\langle \textcolor{blue}{a_{\ell m}} \rangle \neq 0$, \textbf{suggests possible anisotropies or preferred directions in the universe}
\end{frame} \end{frame}
\begin{frame}{The setup} \begin{frame}{The setup}
Real CMB observations are affected by instrumental noise and \textit{sky masking}. So, estimating $C_\ell$ accurately requires simulations. Real CMB observations are affected by instrumental noise and \textit{sky masking}. So, estimating $C_\ell$ accurately requires simulations.
Given $C^{th}_\ell$, used to generate synthetic realizations of the CMB sky Given $C^{th}_\ell$, used to generate synthetic realizations of the CMB sky
\[ \[
\textcolor{blue}{a_{\ell m}} \sim \mathcal{N} (0, C_\ell^{\text{th}}). \textcolor{blue}{a_{\ell m}} \sim \mathcal{N} (0, C_\ell^{\text{th}}).
\] \]
However, this introduces bias, which must be corrected using a decorrelation matrix $W$, and a \textit{sky mask} matrix $M$ which accounts for issues caused by masking effects. However, this introduces bias, which must be corrected using a decorrelation matrix $W$, and a \textit{sky mask} matrix $M$ which accounts for issues caused by masking effects.
Giving us the test statistic (tests the assumption of statistical isotropy): Giving us the test statistic (tests the assumption of statistical isotropy):
\[ \[
S_i = \sum_{j} W_{ij} M_j, S_i = \sum_{j} W_{ij} M_j,
\] \]
Which examines $\langle \textcolor{blue}{a_{\ell m}} \rangle$ across multipole ranges. \\ Which examines $\langle \textcolor{blue}{a_{\ell m}} \rangle$ across multipole ranges. \\
\textbf{\textcolor{red}{Recall:}} $\langle a_{\ell m} \rangle \neq 0$, \textbf{suggests possible anisotropies or preferred directions in the universe} \textbf{\textcolor{red}{Recall:}} $\langle a_{\ell m} \rangle \neq 0$, \textbf{suggests possible anisotropies or preferred directions in the universe}
\end{frame} \end{frame}
@ -192,7 +183,7 @@ Which examines $\langle \textcolor{blue}{a_{\ell m}} \rangle$ across multipole r
\includegraphics[width=0.7\linewidth]{DSE-Test Graph} \includegraphics[width=0.7\linewidth]{DSE-Test Graph}
\caption{The decorrelated band mean spectrum obtained by the seven-year WMAP data [9].} \caption{The decorrelated band mean spectrum obtained by the seven-year WMAP data [9].}
\end{figure} \end{figure}
\textcolor{red}{Remark}In a positively curved space certain multipoles scales being preferred or suppressed in the CMB power spectrum. \textcolor{red}{Remark}In a positively curved space certain multipoles scales being preferred or suppressed in the CMB power spectrum.
\end{frame} \end{frame}