\documentclass[10pt]{beamer} \input{mystyle_beamer.tex} \usetikzlibrary{arrows.meta} \usetikzlibrary{decorations.pathmorphing} \tikzset{zigzag/.style={decorate, decoration=zigzag}} \def \L {2.} \title{Towards Moving Picture Simulations in a Discontinuous Galerkin Framework} \author{Yingjie Wang} \institute{FAU} \addbibresource{ref.bib} \begin{document} \maketitle \begin{frame}{Contents} \tableofcontents \end{frame} \begin{frame}{Outline of the Project} \section{Introduction} \begin{enumerate} \item A first order evolution system, to be named FOZ4c \item An implementation in our discontinuous Galerkin code \texttt{nmesh} \item Simulations of binary black holes with large mass ratio with the moving puncture gauge \end{enumerate} \end{frame} \begin{frame}{Final Goal: binary black holes with large mass ratio} \subsection{binary black holes with large mass ratio} Why binary black holes? \begin{itemize} \item Main sources of gravitational waves \item Simplest two-body problem in general relativity \item Connecting strong field GR with post-Newtonian approximations \end{itemize} Why large mass ratio? \begin{itemize} \item LISA is able to detect extreme mass ratio inspirals (EMRIs) \item Compare with perturbation theory \end{itemize} \end{frame} \begin{frame}{Methods on evolving black holes} \subsection{Methods on evolving black holes} There are two main methods to evolve black holes in numerical relativity: \begin{itemize} \item Excision method: excise the black hole interior from the computational domain, and impose boundary conditions on the excision surface \item Moving puncture method: evolve the black hole as a puncture, and use a suitable gauge condition to avoid the singularity. \end{itemize} \end{frame} \begin{frame}{Methods on evolving black holes: excision} \begin{figure} \centering \includegraphics[width=0.7\textwidth]{imgs/black_hole_excision_mesh.png} \caption{An example mesh using excision method from \cite{Hemberger_2013}.} \end{figure} \end{frame} \begin{frame}{Methods on evolving black holes} \begin{tikzpicture}[>=Latex, line cap=round, line join=round] % causal diamond \draw[thick,red,zigzag] (-\L,\L) coordinate(stl) -- (\L,\L) coordinate (str); \draw[thick,black] (\L,-\L) coordinate (sbr) -- (0,0) coordinate (bif) -- (stl); \draw[thick,black,fill=blue, fill opacity=0.2,text opacity=1] (bif) -- (str) -- (2*\L,0) node[right] (io) {$i^0$} -- (sbr); % null labels \draw[black] (1.4*\L,0.7*\L) node[right] (scrip) {$\mathcal{I}^+$} (1.5*\L,-0.6*\L) node[right] (scrip) {$\mathcal{I}^-$} (0.2*\L,-0.6*\L) node[right] (scrip) {$\mathcal{H}^-$} (0.5*\L,0.85*\L) node[right] (scrip) {$\mathcal{H}^+$}; % singularity label \draw[thick,red,<-] (0,1.05*\L) -- (0,1.2*\L) node[above] {\color{red} singularity}; % % Scwharzschild surface % \draw[thick,blue] (bif) .. controls (1.*\L,-0.35*\L) .. (2*\L,0); % \draw[thick,blue,<-] (1.75*\L,-0.1*\L) -- (1.9*\L,-0.5*\L) % -- (2*\L,-0.5*\L) node[right,align=left] % {$t=$ constant\\in Schwarzschild\\coordinates}; % excision surface \draw[thick,dashed,red] (-0.3*\L,0.3*\L) -- (0.4*\L,\L); \draw[thick,red,<-] (-0.33*\L,0.3*\L) -- (-0.5*\L,0.26*\L) node[left,align=right] {excision\\surface}; % Kerr-Schild surface \draw[green,thick] (0.325*\L,0.325*\L) .. controls (\L,0) .. (2*\L,0); \draw[green,dashed,thick] (0.325*\L,0.325*\L) -- (-0.051*\L,0.5*\L); % Kerr-Schild label \draw[green,thick,<-] (0.95*\L,0.15*\L) -- (1.2*\L,0.5*\L) -- (2*\L,0.5*\L) node[right,align=left] {time slice}; \end{tikzpicture} \end{frame} \begin{frame}{Methods on evolving black holes: moving puncture} \begin{figure} \centering \includegraphics[width=0.42\textwidth]{imgs/moving_puncture_init.png} \includegraphics[width=0.45\textwidth]{imgs/moving_puncture_stable.png} \caption{The embedding of the initial slice (left) and the final slice (right) in the moving puncture method, from \cite{Hannam_2008}.} \end{figure} \end{frame} \begin{frame}{Methods on evolving black holes: moving puncture} \begin{figure} \centering \includegraphics[width=0.7\textwidth]{imgs/moving_puncture_penrose.png} \caption{The numerical time slices in the moving puncture method in the Penrose diagram, from \cite{Hannam_2008}.} \end{figure} \end{frame} \begin{frame}{Discontinuous Galerkin method and \texttt{nmesh}} \subsection{Discontinuous Galerkin method and \texttt{nmesh}} \end{frame} \begin{frame}{References} \printbibliography \end{frame} \end{document}