\documentclass[11pt,oneside]{bidipresentation}
\input{commands}
\DeclareMathSizes{10.95 }{15}{10}{8}
\begin{document}
\begin{figure*}[h]
\begin{center}
\begin{tikzpicture}[ rounded corners ,ultra thick ]	
	\node (0h) at (1.25,1.2) [terminal, label=below: $s_3$]  {{\Large{(0,H)}}};
	\node (1h) at (1.25,2.8) [terminal, label=above: $s_1$]  {{\Large{(1,H)}}};
	\node (0t) at (3.75,1.2) [terminal, label=below: $s_4$]  {{\Large{(0,T)}}};
	\node (1t) at (3.75,2.8) [terminal, label=above: $s_2$]  {{\Large{(1,T)}}};
	\draw [gray][<->] (0h) to (1h);	
	\draw [gray][<->] (0h) to (0t);
	\draw [gray][<->] (0h) to (1t);
	\draw [gray][<->] (1h) to (0t);
	\draw [gray][<->] (1h) to (1t);
	\draw [gray][<->] (0t) to (1t);	
	\path [gray][->] (1h) edge [loop left] node {}();
	\path [gray][->] (0h) edge [loop left] node {}();
	\path [gray][->] (1t) edge [loop right] node {}();
	\path [gray][->] (0t) edge [loop right] node {}();	
\end{tikzpicture}
\end{center}
\caption{\small دسترسی عامل $ a $ به جهان‌های ممکن}
\end{figure*}
\end{document}