\begin{tikzpicture}[state/.style=state with output]
\node[state]{$Z_0$\nodepart{lower}{$y_i=x_s$, $y_r=0$}};
\end{tikzpicture}
Vielen Dank.

\begin{tikzpicture}[state/.style=state with output]
\node[state]{$Z_0$\nodepart{lower}{$y_i=x_s$, $y_r=0$}};
\end{tikzpicture}


\documentclass[11pt,fleqn]{scrartcl}
\usepackage[ngerman]{babel}
\usepackage{tikz}
\usepackage{circuitikz}
\usetikzlibrary{automata}
\begin{document}
\begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto,node distance=2cm,
state/.style=state with output]
\node[state](Z_0){$Z_0$\nodepart{lower}{$y_l=x_s$, $y_r=0$}};
\node[state]at(10,0)(Z_1){$Z_1$\nodepart{lower}{$y_l=0$, $y_r=x_s$}};
\path[every node/.style={font=\Large}]
(Z_0) edge[bend left] node {$x_l$} (Z_1)
edge[loop above] node{$\overline{x_l}$} (Z_0)
(Z_1) edge[bend left] node {$x_r$} (Z_0)
edge[loop above] node{$\overline{x_r}$} (Z_1);
\end{tikzpicture}
\end{document}

Nicht denken, wissen.Patrick1990 hat geschrieben:Ich dachte, das reicht so, […]
\documentclass[ngerman]{scrartcl}
\usepackage[T1]{fontenc}
\usepackage{selinput}
\SelectInputMappings{
adieresis={ä},
germandbls={ß}
}
\usepackage[ngerman]{babel}
\usepackage{tikz}
\usetikzlibrary{arrows,automata}
\usepackage{mathtools} % lädt »amsmath«
\begin{document}
\begin{tikzpicture}[
->,
>=stealth',
shorten >=1pt,
auto,
node distance=2cm,
state/.style=state with output
]
\node[state](Z_0){
$Z_0$
\nodepart{lower}{
\(
\begin{aligned}
y_l &= x_s, \\
y_r &= 0
\end{aligned}
\)
}
};
\node[state]at(10,0)(Z_1){
$Z_1$
\nodepart{lower}{
\(
\begin{aligned}
y_l &= 0, \\
y_r &= x_s
\end{aligned}
\)
}
};
\path[every node/.style={font=\Large}]
(Z_0) edge[bend left] node {$x_l$} (Z_1)
edge[loop above] node{$\overline{x}_l$} (Z_0)
(Z_1) edge[bend left] node {$x_r$} (Z_0)
edge[loop above] node{$\overline{x}_r$} (Z_1);
\end{tikzpicture}
\end{document}